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YOKOHAMA. 


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GIFT  OF 
Daughter  of 
William  Stuart  Smith 


STEAM  YACHTS  AND  LAUNCHES; 


THEIR 


MACHINERY  AND  MANAGEMENT. 


A   REVIEW 

OF  THE  STEAM  ENGINE  AS  APPLIED  TO  YACHTS;   LAWS  GOVERNING 

YACHTS  IN  AMERICAN  WATERS  ;  RULES  FOR  RACING  ;  RULES 

FOR   BUILDING  ;    PILOT    REGULATIONS  ;    SPECIFIC 

TYPES  OF  MACHINERY;  DESIGN  OF  HULLS; 

ETC.,    ETC.,    ETC. 


BY 


C.    P.    KUNHARDT 


NEW   YORK  : 
FOREST    AND    STREAM    PUBLISHING   CO. 

1887. 


VA/33/ 

/rsr 


Copyright, 
FOREST  AND  STREAM  PUBLISHING  Co. 

1887. 


BURR  PRINTING   HOUSE,   NEW  YORK. 


PREFACE. 

STEAM  YACHTING  in  America  has  made  rapid  strides  during 
the  past  ten  years,  the  fleet  of  decked  yachts  now  numbering 
several  hundred,  to  which  may  be  added  nearly  a  thousand  launches 
and  other  small  craft.  The  possibilities  for  future  expansion  are 
almost  beyond  estimation.  Not  only  the  extensive  coast,  but  the 
great  fresh  water  lakes  and  the  vast  river  systems  of  the  American 
continent  are  peculiarly  adapted  to  yachting  under  steam,  whether 
for  hunting  and  fishing  purposes,  excursions,  the  pursuit  of  mechan- 
ical tastes,  or  for  agreeable  methods  of  conveyance. 

With  the  many  radical  improvements  in  safety,  economy  and  speed 
which  have  characterized  the  development  of  machinery  in  recent 
years,  we  may  look  for  constantly  augmenting  accessions  to  the 
steam  pleasure  fleet,  until  it  shall  surpass  in  number  and  variety  the 
combined  fleets  of  other  nations. 

Few  new  buyers  of  steam  yachts  have  more  than  a  vague  compre- 
hension of  the  driving  power  of  their  vessels,  and  few  have  the  time 
or  inclination  to  enter  upon  a  prolonged  scientific  study  of  the  the- 
ory of  steam  machinery,  particularly  when  the  practical  results  to 
them  do  not  seem  proportional  to  the  efforts  put  forth.  This  volume 
is  intended  to  be  sufficiently  comprehensive,  and  elementary  at  the 
same  time,  to  suit  the  yacht  owner's  object  of  acquiring  a  general 
understanding  of  the  subject  as  a  whole,  with  specific  information 
and  data  covering  the  most  recent  practice. 

C.  P.  K. 

NEW  YORK,  May  i,  1887. 


870727 


CONTENTS. 

PAGE. 
THEORY  OF.  THE  STEAM  ENGINE,  9-30 

Earliest  stages.  James  Watt  and  his  improvements.  Hornblower's 
compound  engine  and  separate  condenser.  Saturated  steam.  Marriotte's 
law  of  expansion.  Economy  of  expanding  steam.  Limit  to  cutting  off  in 
practice.  Limit  to  initial  pressure.  High  range  of  temperature  a  neces- 
sity for  economical  working;  but  low  range  in  each  cylinder.  Economy 
of  the  compound  engine  in  practice  compared  with  theoretical  deduc- 
tions. The  direction  improvements  should  take.  Steam  jacketing. 
Superheating.  Friction  of  piping.  Expansion  valves.  Record  of  pro- 
gress made.  Steamer  Hassler.  Triple  expansion  engines.  Steam 
yacht  Gladiator.  Power  derivable  from  the  fuel.  Jacob  Perkins  and 
his  experiments.  Conclusions. 

BOILER  EFFICIENCY,     -  -  30-46 

Cylindrical  boilers.  Requisites  of  good  boilers.  Mechanical  consid- 
erations. Temperature  of  escaping  gases  to  create  draft.  Clyde  return 
tubular  boilers.  Perkins  pipe  boilers.  Evaporative  power  of  coal.  Air 
required  for  combustion.  Forced  draft.  Blowers.  Grate  and  heating 
surface.  Tubes.  Combustion  chambers.  Locomotive  boilers.  Ver- 
tical tubular  boilers.  Corrugated  fire-box  flues.  Naphtha  and  electricity 
as  motors.  Mineral  oil  as  fuel.  Duty  of  yacht  clubs  and  yacht  owners. 
Advance  in  British  practice.  Americans  behind  in  speed.  Highest 
speed  recorded.  Quadruple  engines  and  their  economy. 

BOILER  MOUNTINGS,  -  47-68 

Hydrokineters  to  promote  circulation.  Attachments  enumerated. 
Parts  of  boiler  explained.  Safety  valve.  Smokestacks.  Steam  gauges. 
Mercury  gauges.  Water  gauges  and  cocks.  Fire  plugs.  Low-water 
alarms.  Check  valves.  Inspirators.  Blow-off  valves.  Salinometers 
Feed  pumps.  Expansion  joints. 

THE  ENGINE  AND  ITS  PARTS,      -  -  69-95 

The  slide  valve  and  its  operation.  Eccentrics.  Reversing  gear. 
Indicator  and  diagram.  Horse  power.  The  Pantograph.  Condensers. 
Outboard  condensing  pipes.  Jet  condensers.  Revolution  counters. 

THE  SCREW,  *  -  96-106 

Paddlewheels  considered.  The  feathering  wheel.  Operation  of  the 
screw.  Nomenclature  of  the  screw.  Pitch.  Slip,  apparent  and  real. 
Experiment  the  only  guide.  Resistance  at  high  speeds.  Various  kinds 
of  screws.  Loss  of  power  between  cylinder  and  screw.  Formulae  for 
resistance  and  power  untrustworthy.  Comparison  the  only  guide  to  ap- 
portioning driving  power.  Consumption  of  fuel  at  various  speeds. 


Contents. 


LAWS  APPLICABLE  TO  STEAM  YACHTS,  -  107-128 

Status  of  steam  yachts.  No  license  fees  for  inspection.  Special 
license  to  yacht  engineers,  masters  and  pilots.  '  The  Revised  Statutes 
relating  to  licensing  yachts.  Boiler  plate.  Test  pressures.  Thickness 
of  tubes.  Space  around  boilers.  Manholes.  Fire  plugs.  Gauges 
and  safety  valves.  Seacocks.  Lifeboats  and  equipment.  Rafts. 
Bulkheads.  Steam  launches.  Provisions  against  fire.  Licenses  to 
officers.  Engine-room  signals.  Annual  inspection.  Lock  safety 
valves.  Pilot  rules  for  lake  and  seaboard.  Pilot  rules  for  Western 
rivers.  Lights  for  steam  vessels.  Case  of  the  Yosemite  (see  also  Ad- 
denda, at  end  of  volume). 

EXTRACTS  FROM  LLOYDS'  RULES,     -  -  129-136 

Stern  framing.  Reverse  frames  under  engines  and  boilers.  Gar- 
board  strakes.  Bulkheads.  Skylights.  Coal  bunkers.  Material  for 
boilers.  Stays  and  rivets.  Mountings  required.  Strength  of  material. 
Annual  surveys.  Characters  given  in  Lloyds'  Yacht  Register.  Scant- 
ling for  wood  and  iron  yachts.  Anchors  and  chains.  Butts  and  rivet 
work. 

RACING  STEAM  YACHTS,  -   137-145 

Objects  of  racing.  Time  allowance  by  length  and  its  shortcomings. 
Emory  table  of  allowance;  C.  H.  Haswell's  formula  preferable.  Length 
should  be  included. 

MANAGEMENT  AND  CARE  OF  MACHINERY,  -   146-154 

Eilling  the  boiler.  Lighting  fires.  Safety  valve.  Foaming.  The 
feed.  Low  water.  Inspirator  fails  to  feed.  Blowing  off.  Banking 
fires.  Removing  sediment.  Split  tubes.  Blisters.  General  care. 
Laid  up.  Getting  under  way.  Attendance  while  running.  Thumping. 

PRINCIPAL  TYPES  OF  YACHT  MACHINERY. 

Perkins  high  pressure  system,  -                                        -                          -155 

Herreshoff  system,      -  164 

Yertical  direct-acting  Engines,  -                                                                   -       1 79 

Sternwheel  boats,         -  192 

Seagoing  launches,  -       195 

Coasting  yachts,  198 

Cruising  steamers,  -             -       200 

Dimensions  of  steam  yachts,  203 

Wells  balance  engine,       -  -       207 

Colt  disc  engine,  212 

Cheap  machinery  for  small  craft,  -       218 

Shipman  kerosene  engine,       -  221 

Oscillating  engines,  -       223 

Kane's  porcupine  boiler,         -  227 

Naphtha  launches,  -       229 

THE  DESIGN  OF  HULLS,  -  233-236 

No  precise  directions  can  be  laid  down.  Ballast  in  steam  yachts  not 
usual.  Resistance  and  beam.  Proportions  determined  by  experience. 
Consideration  of  form  of  least  resistance.  Limits  to  its  adoption  in 
steam  vessels.  Proportions  of  high-speed  torpedo  boats.  Character  of 
cross-section  and  waterlines  dependent  upon  individual  preference. 

ADDENDA,  -  237-239 

.    Lights  on  steam  yachts  and  useful  tables. 


ILLUSTRATIONS. 


PAGE. 

Steam  Yacht  Shaugraun ' Frontispiece. 

Inverted  Launch  Engine 15 

Double  Direct-acting  Engine 17 

Compound  Inverted  Surface  Condensing  Engine 19 

Machinery  of  Steam  Yacht  Gladiator 25,  27,  28,  29 

Return  Tubular  Boiler 32 

Clyde  Boiler 33 

Perkins  Pipe  Boiler 34 

Doghouse  Boiler 36 

Sturtevant  Blower.  . . 37 

Locomotive    Boiler 39 

Vertical  Tubular  Boiler 40 

Corrugated  Flue 41 

U.  S.  Launch  Return  Tubular  Boiler 48,  49 

Safety  Valve 51 

Marine  Pop  Safety  Valve 52 

Bourdon  Steam  Gauge 53,  54 

Mercury  Gauge 55 

Combination  Gauges 56 

Low  Water  Alarm 58 

Check   Valve 59 

Hancock    Inspirator 60 

Salinometer 63 

Duplex  Feed  Pump 65,  66 

Plunger  Pump 68 

Section  of  Cylinder  and  Valve 70,  71 

Reversing  Gear 74 

Thompson  Indicator , 76 

Indicator  Diagram 78 

Pantograph 82,  83 

Wheeler's  Surface  Condenser 87,  88,  89 

Worthington  Jet   Condenser 92 

Engine  Room  Counter 94 

Willard's  Propeller  Wheel 98 


Illustrations.  vii 

Thorneycroft's  Screw 102 

Giant  Propeller 103 

Duncan's  Propeller 104 

Perkins  Condenser  and  Still 156 

Perkins  Engine 158,  161,  162 

Herreshoff  Coil  Boiler . , 169 

Herreshoff  Engines 174,  175 

Stiletto.  U.  S.  X 178 

Katrina,    Launch 180 

Plan  of  Soft.  Yacht 181 

Open  Steam  Launch ' . 183 

Plans  of  Triple  Screw  Launch 184 

Mohawk,  Steam  Launch 185 

Plans  of  Revenue  Cutter 186 

Plans  of  Small  Trading  Steamer 187,  188 

Willard  High  Speed  Engine 190,  191 

Sternwheel  Boats 192,  193 

Cruising  Launch 195 

Falcon,   Coasting  Steam  Yacht 197,  198 

Chemcheck,  Cruising  Steam  Yacht 201 

Carmen,   Seagoing  Steam  Yacht 204,  205 

"SYells  Compound  Balanced  Engine 209 

Colt  Disc  Engine .' 213,  214,  215 

Shipman  Kerosene  Engine 219,  221 

Shipman  Launch 222 

Kriebel  Oscillating  Engine 224,  225 

Kane's  Porcupine  Boiler  and  Engine 227 

Naphtha  Launches 229,  230,  231 

Naphtha  Launch  Engine 232 


STEAM  YACHTS  AND  LAUNCHES. 


i. 

THEORY     OF     THE     STEAM     ENGINE. 

IX  the  first  stages  of  its  development,  the  steam  engine  was  a 
single-acting  affair  worked  without  expansion.  That  is  to  say, 
steam  was  admitted  on  one  side  of  the  piston  only,  the  whole  length 
of  the  stroke  being  followed  up  by  a  continuous  supply  of  steam 
from  the  boiler.  The  return  stroke  was  accomplished  by  shutting 
off  the  steam  and  injecting  cold  water  under  the  piston,  thereby 
condensing  the  steam  and  creating  a  vacuum  in  the  cylinder.  The 
pressure  of  the  atmosphere,  14.7  Ibs.  per  square  inch,  acting  upon  the 
upper  side  of  the  piston,  would  force  it  to  descend  preparatory  to 
the  next  upward  stroke. 

Between  the  years  1775  and  1785,  the  untiring  industry  and  genius 
of  James  Watt  had  wrought  such  material  improvements  upon  the 
original  ''atmospheric  engine"  of  Newcomen,  that  the  same  princi- 
ples and  general  arrangements  continue  to  prevail  in  the  standard 
motor  of  the  present  day.  Under  the  name  of  the  Cornish  pump- 
ing engine,  almost  the  identical  process  and  mechanism  of  Watt  are 
preserved,  and  until  quite  recently  this  was  the  most  economical 
of  all  engines  used  for  drawing  water  from  deep  mining  shafts. 
Under  Watt's  patents  relating  to  working  by  the  expansion  of 
steam  in  a  double-acting  engine,  in  which  the  steam  enters  on  each 
side  of  the  piston  alternately,  the  opposite  side  being  in  communica- 
tion with  the  condenser,  the  whole  range  of  modern  refinements  in 


io  Theory  of  the  Steam  Engine. 


.methods'  of.  ^xec&tion  is  included.  The  most  important  and  profit- 
,f  -all  the  ;nuunierous  progressive  steps  toward  perfection  origi- 
by  "Watt  "was  trie  practical  application  of  working  by  expansion. 

Strange  to  say,  the  true  value  of  this  feature  remained  almost 
dormant  for  a  long  time,  and  has  only  received  full  recognition  of 
late  with  the  general  introduction  of  high-pressure  and  compound 
engines,  as  the  means  for  utilizing  the  benefits  to  be  derived  from 
the  elastic  properties  of  steam.  Although  individual  leaders  in  the 
engineering  world  never  lost  sight  of  this  great  essential  to  the 
economic  transmission  of  heat-energy  with  steam  as  the  conveyor, 
the  majority  rested  content  with  the  half-way  results  achieved 
through  low  pressures  and  a  low  rate  of  expansion.  Undoubtedly 
the  mechanical  difficulties  in  the  way  of  providing  apparatus  of  suf- 
ficient strength  to  withstand  the  immense  pressures  now  common 
had  much  to  do  with  keeping  practice  far  in  the  rear  of  theory  and 
small  scale  experiments. 

At  this  period  there  are  still  some  who  refuse  to  concede  the  mani- 
fest advantages  of  pursuing  to  the  mechanical  limit  the  clear  dic- 
tates of  science,  through  confounding  the  primary  source  of  saving 
in  the  boiler  with  the  mere  mechanism  of  transmission  represented 
in  the  engine.  Fortunately  the  actual  results  obtained  from  working 
at  high  pressures  and  high  rates  of  expansion  have  held  out  so  much 
encouragement  that  the  energy  displayed  in  recent  years  in  the 
direction  clearly  pointed  out  by  Watt  a  century  ago  is  destined  to 
lead  up  to  attainments  which  would  have  been  considered  visionary 
a  decade  ago. 

The  impression  that  the  so-called  modern  system  of  "  compound- 
ing "  is  a  recent  invention  is  as  far  from  the  truth  as  that  there  is  a 
direct  profit  in  the  compound  engine.  The  latter  contrivance  is  al- 
most contemporaneous  with  the  birth  of  the  steam  engine  itself,  and 
was  the  natural  expression  of  the  value  set  upon  expansion  by  Watt 
and  the  philosophers  of  his  period.  In  1781,  Jonathan  Hornblower 
brought  out  his  compound  or  double-cylinder  engine,  in  which  the 
exhaust  steam  from  a  small  cylinder  was  passed  into  a  larger  cham- 
ber for  expansion  and  thence  into  a  separate  condenser.  Watt 
claimed  priority  in  the  separate  condenser  and  also  in  this  arrange- 


Theory  of  the  Steam  Engine.  1 1 

ment,  on  the  ground  that  it  was  nothing  more  nor  less  than  working 
steam  expansively,  the  two  cylinders  being,  only  a  mechanical  divi- 
sion of  his  single  cylinder  in  which  steam  was  cut  off  at  a  fraction  of 
the  stroke.  The  claim  was  a  just  one,  for  the  compound  engine 
differs  from  the  single  expansion  cylinder  only  in  arrangement  of 
parts  and  not  at  all  in  point  of  principle.  Many  years  later  Rankine, 
in  his  investigations  of  steam  and  other  prime  movers,  enunciated 
the  law  that,  "  So  far  as  the  theoretical  action  of  the  steam  on  the 
piston  is  concerned,  it  is  immaterial  whether  expansion  takes  place 
in  one  cylinder,  or  in  two  or  more  cylinders." 

The  true  source  of  increased  efficiency  in  modern  practice  is  to  be 
ascribed  to  the  higher  initial  or  boiler  pressures  adopted,  permitting 
correspondingly  higher  rates  of  expansion  ;  in  other  words  to  profit- 
ing from  the  greater  elasticity  of  steam  at  greater  pressures,  as  the 
following  considerations  will  explain. 

According  to  Marriotte's  law,  the  pressure  of  gases  varies  inversely 
as  the  spaces  occupied.  If,  for  example,  a  gas  having  40  Ibs.  pres- 
sure per  square  inch  be  expanded  to  twice  its  former,  volume,  the 
pressure  per  square  inch  will  have  been  reduced  to  20  Ibs.  If  it  be 
allowed  to  expand  to  three  times  the  original  volume,  the  pressure 
will  be  one-third  of  40  or  13.33^5.,  and  so  on.  In  practice,  there 
will  be  a  deviation  from  this  theoretical  law  in  the  cylinder  of  a 
steam  engine,  owing  to  the  variations  in  temperature  which  affect 
the  pressure  very  materially,  unless  the  steam  be  superheated,  when 
it  acquires  the  properties  of  a  permanent  gas,  or  unless  the  tempera- 
ture of  the  cylinder  can  be  kept  nearly  up  to  that  of  the  steam  to 
prevent  condensation  of  saturated  steam. 

The  term  saturated  steam  applies  to  steam  only  sufficiently  heated 
to  remain  in  the  shape  of  vapor,  an  intermediate  state  between  the 
fluid  and  permanently  gaseous  state.  Heating  saturated  steam 
converts  the  small  globules  of  water  held  in  suspension  into  steam, 
the  whole  passing  ultimately  into  the  superheated  state,  if  the  pres- 
sure be  not  increased.  Saturated  steam,  upon  cooling,  will  be  pre- 
cipitated or  condensed  into  water. 

The  chief  cause  for  the  failure  of  steam  in  practice  to  meet  the 
relations  expressed  in  Marriotte's  law  is  the  intermittent  chilling  of 


12 


Theory  of  the  Steam  Engine. 


the  cylinder  on  the  exhaust  side  of  the  piston,  owing  to  communica- 
tion with  the  condenser,  in  which  the  temperature  is  necessarily  low. 
When,  on  the  next  stroke,  live  steam  is  admitted,  it  finds  the  metal 
of  the  cylinder,  its  head  and  piston  cooled  down  to  such  a  degree 
that  partial  condensation  of  the  saturated  steam  takes  place  with 
corresponding  reduction  in  pressure  as  the  piston  proceeds.  After 
the  steam  has  been  cut  off,  the  temperature  rapidly  falls  with  the 
expansion  during  the  remainder  of  the  stroke,  bringing  the  tempera- 
ture lower  than  that  of  the  metal.  The  condensed  particles  on  the 
surface  of  the  metal  are  then  re-evaporated,  absorbing  heat  from  the 
metal  at  the  end  of  the  stroke  which  passes  off  into  the  condenser  as 
so  much  additional  energy  wasted.  In  spite  of  these  deviations, 
Marriotte's  law  is  employed  in  ascertaining  the  mean  pressure  on 
the -piston. 

Suppose  the  annexed  diagram  to  represent  a  cylinder,  in  which  the 
steam  is  cut  off  at  half  stroke.  Divide 
the  cylinder  into  say  ten  equal  parts. 
If  the  initial  pressure  be  taken  as  i,  the 
pressure  at  each  of  the  five  divisions  up 
to  half  stroke  will  also  be  represented 
by  i.  At  B  the  steam  is  cut  off  and  ex- 
pansion begins.  At  the  sixth  division 
the  pressure  will  be  reduced  to  £  of 
i  =-8333,  since  the  spaces  occupied  at 


FIG.  i 


B 


7/4*3 


the  fifth  and  sixth  divisions  are  inversely 
to  one  another  as  6  to  5.  At  the  seventh 
division,  the  pressure  will  have  been  re- 
duced to  f  of  i  =.7143.  At  the  eighth 
division  to  ^  of  i  ==.6250,  and  so  on. 
At  the  tenth  or  end  of  stroke  the  pres- 
sure will  be  one-half  the  initial,  or  0.5, 
the  space  occupied  being  twice  as  great 
as  when  the  steam  was  cut  off.  Had 
the  steam  port  been  closed  at  one- 
quarter  stroke,  the  final  pressure  would  have  been  one-quarter 
of  the  initial.  The  mean  of  all  the  ascertained  pressures  after 


£000 


Theory  of  the  Steam  Engine.  1  3 

cutting  off  is  found  by  adding  them  and  dividing  by  the  num- 
ber of  spaces,  as  performed  in  the  diagram.  The  mean  of  this  and 
the  "following  steam"  for  the  first  half  of  the  stroke  is 


2 

the  accuracy  of  which  depends  upon  the  number  of  divisions  intro- 
duced. 

If  the  pressures  be  scaled  off  on  their  respective  divisions  and  a 
curve  passed  through  the  extremities,  as  B  D,  it  will  be  found  to  be 
a  hyperbola.  From  the  foregoing  we  have  for  the  pressure  at  any 
point  the  formula, 

P'=     PL 


L' 

in  which  P  is  the  initial  pressure,  L  the  length  of  the  stroke  com- 
pleted when  steam  is  cut  off  and  L'  the  length  of  stroke  to  the 
point  P'. 

Example  :     The  stroke  of  an  engine  is  60  inches,  and  cuts  off  at 
30  inches  ;  initial  pressure  is  4olbs.;  required  the  pressure  at  end  of 

stroke  : 

,      30x40 


60 

The  effective  or  "unbalanced"  pressure  upon  the  piston  will  be 
modified  by  whatever  back  pressure  may  exist  on  the  opposite  side 
of  the  piston.  If  the  engine  were  non-condensing,  the  exhaust 
would  lead  into  the  open  air  against  the  atmospheric  pressure  of 
14.7  Ibs.  to  the  square  inch.  The  effective  pressure  at  end  of  stroke 
in  the  above  example  would  be  20  —  14.7  =  5.3  Ibs. 

If  the  engine  is  of  the  condensing  kind,  the  exhaust  would  lead 
into  the  more  or  less  perfect  vacuum  of  the  condenser,  and  the  back 
pressure  would  vary  accordingly,  usually  from  2  to  3  Ibs.,  augmented 
somewhat  by  the  back  pressure  of  the  steam  itself  while  escaping 
on  the  exhaust  side  through  the  pipes  connecting  with  condenser. 
The  mean  pressure,  calculated  from  the  diagram  as  .6456,  was  stated 
to  be  only  an  approximate  result.  By  increasing  the  number  of 
divisions  very  greatly,  a  larger  and  nearly  correct  average  would  be 
returned  in  the  figure  .693,  the  "hyperbolic  logarithm"  of  2.  Simi- 
larly for  cutting  off  at  one-quarter  stroke,  the  ratio  of  pressure  for 


14  Theory  of  the  Steam  Engine. 

the  expansion  through  the  remaining  three-quarters  of  the  stroke 
will  be  expressed  by  the  hyperbolic  logarithm  of  4,  or  1.386.  From 
a  table  of  such  logarithms  the  ratio  of  pressure  can  be  obtained  for 
any  point  of  cut-off  by  simple  inspection,  doing  away  with  laborious 
calculation  by  a  large  number  of  divisions  in  each  case.  The  figures 
cited  by  way  of  example  are  enough  for  our  purpose. 

If  the  cylinder  A  C  be  supposed  to  measure  two  units  in  length, 
and  its  cross  section  one  unit  in  area,  then  the  work  performed  dur- 
ing the  first  half  stroke,  while  the  piston  is  forced  from  A  to  B  by 
live  steam  having  an  initial  pressure  of  i,  will  be  expressed  by 
i  X  i  X  i  =  area  X  pressure  X  distance  traveled.  The  work  per- 
formed during  the  latter  half  of  the  stroke  will  be  expressed  by 

1  X.6pX  i  =.69,  and  the  total  work  throughout  the  entire  stroke  by 
the  sum  of  the  two,  or  i +.69  =  i  .69.     Had  the  steam  been  exhausted 
at  B  and  not  used  expansively  from  B  to  C,  the  work  performed 
would  have  been  only  i  instead  of  1.69,  the  quantity  of  steam  used 
being  the  same  in  both  cases.     Hence,  by  utilizing  the  elasticity  of 
the  steam  in  prolonging  the  stroke  after  cutting  off  the  supply,  the 
gain  in  work  is  represented  by  69  per  cent.     Had  the  steam  port  not 
been  closed  at  all,  but  had  we  followed  up  with  live  steam  for  the 
whole  stroke,  the  work  performed  would  have  been  1X1X2  (area  X 
pressure  X  distance  A  BC)  =  2.     By  cutting  off,  the  work  per- 
formed was  reduced  from  2  to  1.69.     For  drawing  fair  inferences, 
however,  the  work  performed  should  be  made  equal  in  both  cases. 
This  can  be  done  by  increasing  the  initial  pressure  when  cutting 
off,  so  that  the  mean  pressure  may  be  sufficiently  great  to  accom- 
plish the  same  total  work  when  cutting  off  at  half  stroke  as  with  a 
steady  pressure  of   i.     Call    the  desired   initial   pressure    X,    then 

2  :  1.69  ::  X  :  0.845  X,  (the  mean  pressure).     The  mean  pressure  de- 
rived from  the  new  initial  pressure  sought  must  of  course  be  the 
same  as  the  mean  pressure  when  the  full  stroke  is  followed  up.     But 
this  we  have  assumed  to  be  i,  hence  .845  X  =  i  lb.,or  X  =  1.18  Ibs., 
the  new  initial   pressure  sought.     In  cutting  off  with  this  initial 
pressure  of   i.iSlbs.,  only  half  the  cylinder  full  of  steam  is  used 
to   every    full   cylinder  when    following  up  full  stroke  with   i  Ib. 
pressure.     The    difference   between   1.18    and    2    therefore    repre- 


Theory  of  the  Steam  Engine,  15 

sents  the  saving  in  steam  by  starting  with  higher  initial  pressure 
but  cutting  off  at  half  stroke.  This  difference  is  0.82  or  41  per  cent. 
This  41  per  cent,  is  the  volume  of  steam  saved  at  the  cylinder  en- 
trance in  performing  a  certain  amount  of  work  or  running  a  certain 


FIG.  2. — INVERTED  DIRECT-ACTING  LAUNCH  ENGINE.     N.  Y.  SAFETY  STEAM 

POWER  Co. 


1 6  Theory  of  the  Steam  Engine. 

distance,  but  it  is  not  identical  with  the  amount  of  fuel  saved,  since 
it  requires  more  coal  to  raise  steam  to  the  higher  initial  pressure  in 
the  first  place  with  correspondingly  increased  loss  in  heat  passing  out 
of  the  chimney  to  produce  the  required  draft,  loss  in  radiation,  fric- 
tion and  condensation  in  reaching  the  cylinder.  The  actual  saving  in 
fuel  will  be  found  to  be  about  20  per  cent. 

The  economy  of  working  expansively  with  increased  pressure  is 
evident  from  the  foregoing. 

Theoretically  there  is  no  limit  to  the  benefits  to  be  derived  from 
expansion.  Cutting  off  at  one-seventh  would  effect  double  the  work 
done  by  "following"  full  stroke,  and  if  we  could  start  with  an  in- 
finitely great  pressure,  we  could  cut  off  at  an  infinitely  small  fraction 
and  effect  the  maximum  saving.  As  there  is  always  more  or  less 
back  pressure  on  the  exhaust  side,  the  theoretical  limit  of  cutting  off 
for  a  given  initial  pressure  would  be  found  at  that  point  which  would 
leave  for  the  terminal  pressure  at  the  end  of  the  stroke  enough  to 
balance  the  back  pressure  with  something  to  spare  for  overcoming 
the  friction  of  the  engine. 

In  actual  practice  this  limit  is,  however,  greatly  curtailed  by  a  fact 
already  referred  to,  the  lowering  of  the  temperature  and  consequent 
loss  in  power  with  every  increase  in  expansion.  Thus  what  we 
would  be  gaining  theoretically  by  resorting  to  high  rates  of  expan- 
sion may  in  practice  be  lost  through  the  accompanying  fall  in  the 
temperature  of  the  steam.  Experience  has  established  that  as  a  rule 
no  economy  follows  expansion  in  a  single  cylinder  to  a  greater  num- 
ber of  volumes  than  one-half  the  square  root  of  the  steam  pressure, 
or  algebraically,  */2  V^T  wnere  P  is  the  pressure  in  pounds  per 
square  inch.  That  is,  we  should  cut  off  at  about  %  for  15  to  20  Ibs. 
pressures,  at  y$  for  say  36  Ibs.,  at  %  for  64  Ibs.  and  i  for  icolbs. 
If  we  were  to  expand  beyond  the  fractions  determined  by  experience, 
the  consequence  would  be  a  lowering  of  the  mean  pressure  as  ex- 
plained. This  would  have  to  be  made  good  by  greater  initial  or 
boiler  pressure,  which  implies  extra  consumption  of  fuel,  and  the 
limits  of  practical  economy  would  have  been  overstepped  in  the 
pursuit  of  a  theoretical  truth. 

For  a  long  time  steam  was  treated  as  a  gas  of  fixed  properties,  yet 


Theory  of  the  Steam  Engine.  1 7 

every-day  routine  was  demonstrating  it  to  be  most  unstable  and  ex- 
ceedingly sensitive  to  differences  in  temperature.  It  is  mainly 
through  the  full  appreciation  of  this  instability  that  the  recent  great 
advances  in  the  practice  have  had  their  birth.  The  inferences  from 
Marriotte's  law  were  plain  enough.  Steam  should  be  used  at  great 
pressure  and  at  a  great  rate  of  expansion.  So  far  as  pressure  was 
concerned,  it  resolved  itself  into  the  question  of  constructing  boilers 
to  suit.  The  mechanical  limit  to  possibilities  in  construction  would 
be  the  only  restriction  to  initial  pressure.  But  when  it  comes  to 
great  expansion  in  the  single  cylinder,  formerly  in  universal  use, 
practice  has  been  found  to  fail  to  meet  theory  to  the  extent  expected. 
The  great  range  in  temperature  from  beginning  to  end  of  stroke 


FIG.  3. — DOUBLE  INVERTED  DIRECT- ACTING  YACHT  ENGINE,  WITH  INDEPEND- 
ENT  CUT-OFF.     CLUTE  &  Co.,  SCHENECTADY,  N.  V. 


1 8  Theory  of  the  Steam  Engine. 

caused  such  serious  losses  from  condensation  and  re-evaporation, 
besides  those  due  to  conduction  and  radiation  of  the  metal,  that  the 
mean  pressure  was  sensibly  reduced  and  the  gain  in  economy  did  not 
off-set  other  drawbacks.  The  revival  of  Hornblower's  method,  in 
other  words  the  introduction  of  the  compound  engine,  overcomes  in  a 
great  measure  the  difficulty  experienced  in  the  single  cylinder,  and 
supplies  us  with  the  mechanical  means  of  profiting  from  the  physical 
advantage  of  working  with  high  rate  of  expansion.  We  are  enabled 
in  the  compound  arrangement,  to  achieve  the  vital  desideratum 
for  successful  expansion,  that  is  a  low  range  of  temperature  in 
each  cylinder,  giving  a  high  range  for  both.  Therein  lies  the 
superiority  of  Hornblower's  system  over  the  single  long  chamber  re- 
quired in  the  simple  engine.  The  process  of  expansion  is  cut  short 
in  the  first  cylinder  and  then  finished  in  the  second,  so  that  we  have 
a  smaller  range  of  temperature  in  each  than  if  the  expansion  had 
been  wholly  carried  out  in  one  cylinder  and  consequently  less  loss 
of  heat  energy.  The  saving  thus  effected  in  power  represents  in 
turn  a  saving  in  fuel,  followed  by  a  train  of  advantages  of  special 
application  in  yacht  construction. 

With  a  given  amount  of  fuel,  the  economical  machine  will  propel 
the  hull  to  a  greater  distance,  or  taking  the  distance  as  the  basis  of 
comparison,  the  economical  machine  can  be  supplied  from  smaller 
coal  bunkers.  The  weight  saved  can  be  taken  from  the  yacht's  dis- 
placement and  higher  speed  brought  about  by  fining  away  the  model, 
or,  what  is  the  same  thing,  less  resistance  at  the  same  speed  and 
therefore  less  expenditure  in  driving  power,  thereby  making  a  saving 
at  both  ends.  The  boilers  will  be  smaller  and  lighter  and  the  same 
holds  good  of  the  engines.  High  pressures  can  be  introduced  with 
the  compound  engine  with  less  weight  of  metal  and  wear  than  in 
the  simple  cylinder,  as  the  difference  between  initial  and  terminal 
pressure  in  each  cylinder  will  not  be  as  great  and  the  compound  will 
also  be  smoother  in  running.  Hence,  higher  piston  speed  can  be 
employed,  which  is  equivalent  to  a  further  saving  by  shortening  the 
period  during  which  the  metal  in  contact  with  the  steam  can  alter- 
nately heat  and  cool.  The  more  rapidly  the  piston  travels,  the 
greater  the  number  of  revolutions  and  the  finer  the  pitch  of  the 


FIG.  4. 


A.  High  pressure  cylinder. 

B.  Low  pressure  cylinder. 

C.  Steam  from  boiler. 

D.  Valve  chests,  containing  slide  valves. 

E   F.     Connecting  rods  attached  to  crossheads 

P. 

G.  H.     Cranks  on  shaft. 

I   J.     Eccentrics,  giving  motion  to  valve  gear,      j 
K.     Shaft. 
L.     Pillars  supporting  cylinders.  [19]    j 


Crank  shaft  bearings. 

Surface  condenser. 

Reversing  gear  and  lever. 

Piston  crossheads  working  in  slipper  guides. 

Air  and  Circulating  Pumps  back  of  con- 
denser are  worked  by  beams  receiving 
motion  from  piston  crossheads. 

Valve  stems  receiving  motion  from  Stephen- 
son  link  gear. 

Exhaust  pipe  leading  to  condenser: 


2O  Theory  of  the  Steam  Engine. 

screw,  torsion  and  strain  being  correspondingly  reduced,  allowing 
lighter  construction,  or  so  much  additional  saving  in  weight. 

If  it  were  possible  to  devise  a  perfectly  non-conducting  substance 
from  which  to  construct  a  cylinder,  the  simple  expansive  engine 
would  be  the  best  machine  so  far  as  profit  from  expansion  itself  is 
concerned,  for  there  is  a  special  loss  in  the  compound,  due  to  expan- 
sion of  steam  while  passing  from  first  to  second  cylinder.  This  loss 
is  known  as  the  "drop,"  being  the  difference  between  terminal  pres- 
sure in  the  high-pressure  cylinder  and  initial  pressure  in  the  low. 
The  amount  of  this  drop  depends  upon  details  of  construction,  and 
is  found  by  comparing  "  indicator  diagrams  "  taken  from  both 
cylinders.  Until  a  perfectly  non-conducting  lining  for  cylinders  is 
devised,  the  loss  due  to  "  drop  "  in  the  compound  is  not  enough  to 
destroy  the  benefits  derived  in  other  respects. 

Summarizing  the  foregoing  we  draw  the  general  conclusion  that 
success  in  economical  propulsion  by  steam  is  directly  promoted  by 
working  between  the  widest  possible  limits  of  temperature  and 
devoting  the  utmost  care  to  providing  against  losses  by  dissipation 
of  heat  in  directions  in  which  it  will  not  contribute  to  the  production 
of  useful  power. 

The  tendency  in  all  attempts  at  fmprovements  should  be  toward 
high  pressure,  more  perfect  vacuum,  greater  expansion,  steam  jacket- 
ing or  superheating,  non-conducting  protectors  against  waste,  and 
higher  piston  speeds. 

Steam  jacketing,  which  consists  of  admitting  live  steam  to  a 
special  chamber  surrounding  the  cylinder  to  preserve  the  heat  of  the 
metal  of  the  latter  as  nearly  even  as  may  be,  has  been  found  advan- 
tageous in  engines  using  saturated  steam,  but  of  little  or  no  benefit 
where  the  steam  is  used  dry.  It  may  often  appear  that  steam  jacket- 
ing is  of  no  benefit  with  the  use  of  low  steam,  and  yet  profitable  in 
another  engine  using  high  steam,  though  this  is  contrary;  to  accepted 
views  among  engineers.  But  the  value  of  jacketing  varies  with  the 
condition  of  the  steam  rather  than  with  its  pressure.  This  will  ex- 
plain the  contradictory  results  observed  in  practice. 

Superheating  the  steam  is  preferable.  This  consists  of  passing 
the  saturated  steam  from  the  boiler  through  an  arrangement  of  tubes 


Theory  of  the  Steam  Engine.  21 

or  plates  which  take  up  some  of  the  heat  escaping  into  the  chimney. 
Superheated  steam  is  less  liable  to  loss  of  temperature  through  con- 
densation in  the  cylinder. 

The  arrangement  of  piping  and  valves  should  of  course  be  such 
as  to  interfere  as  little  as  possible  with  the  free  movement  of  the 
steam  to  obviate  undue  friction  and  back  pressure.  In  its  mechanical 
aspects,  a  good  engine  should  have  extreme  accuracy  in  the  fitting  of 
parts,  ample  area  and  durability  of  bearings  and  wearing  parts,  con- 
tinuous lubrication,  freedom  from  shock  and  play  of  parts. 

Very  much  must  always  depend  upon  the  intelligence  and  skill  of 
persons  charged  with  the  regulating  of  the  machinery.  Especially 
is  this  true  of  the  compound  engine.  The  key  to  good  management 
lies  in  frequent  examination  of  indicator  diagrams  taken  under  vary- 
ing conditions,  and  from  them  settling  upon  the  most  profitable 
points  of  cut-off  for  each  cylinder  of  the  compound  if  fitted  with 
separate  valves  and  gear.  The  use  of  expansion  valves  on  the  low- 
pressure  cylindei  will  not  so  much  alter  the  total  work  done  by  the 
engines  as  it  will  the  ratio  of  work  in  the  two  cylinders.  The 
judicious  use  of  these  valves,  especially  at  low  speeds,  will  increase 
the  total  performance  per  unit  of  fuel,  but  their  principal  purpose  is 
to  regulate  the  work  done  in  each  cylinder.  If  these  valves  are  not 
used  at  low  speeds,  it  will  be  found  that  the  work  done  in  the  low 
cylinder  will  hardly  be  enough  to  overcome  weight  and  friction,  and 
the  low  pressure  addition  may  actually  prove  a  drag  on  the  high- 
pressure  cylinder. 

The  higher  the  rate  of  expansion  in  the  low-pressure  cylinder,  the 
greater  the  pressure  in  the  intermediate  reservoir  and  the  back  pres- 
sure in  the  high-pressure  cylinder.  Hence,  increasing  the  rate  of  ex- 
pansion in  the  low-pressure  cylinder,  while  developing  the  power  in 
that  cylinder,  will  correspondingly  curtail  the  power  developed  in  the 
high  pressure  cylinder. 

If  no  expansion  valves  are  fitted  to  the  low-pressure  cylindei,  ex- 
periments with  varying  cut-off  can  be  carried  out  within  limits  by 
means  of  the  links  giving  motion  to  the  slide  valve. 

The  progress  made  in  the  marine  engine,  from  its  earliest  days  up 
to  the  present,  is  simply  a  record  of  increased  pressure  and  expansion. 


2  2  Theory  of  the  Steam  Engine. 

From  5  to  lolbs.  was  the  usual  pressure  in  the  time  of  Watt.  The 
first  engines  for  screw  propulsion  used  steam  at  15  Ibs.  The  mechan- 
ism was  of  the  geared  kind  with  jet  condensers,  and  consumed  7  to 
10  Ibs.  of  coal  per  Indicated  Horse  Power  per  hour.  A  little  later 
the  direct-acting  engine  was  introduced  with  steam  at  20  ibs.,  5  to 
6  Ibs.  being  the  fuel  consumption.  Higher  pressures  and  greater  ex- 
pansion followed  slowly.  Then  the  surface  condenser  with  its  more 
perfect  vacuum  than  the  jet  condenser  brought  down  the  consump- 
tion to  3  and  4  Ibs.  The  boiler  pressure  rose  to  25  Ibs.  as  the 
troubles  from  boiler  incrustation  were  partly  overcome. 

The  movement  toward  still  higher  steam  was  kept  up  until  it  has 
reached  60  to  75  Ibs.  in  American  river  boats,  and  over  loolbs.  in 
the  non-condensing  direct-acting  engines  of  the  Western  rivers.  -In 
the  well-known  "  floating  palaces  "  running  on  Long  Island  Sound, 
the  consumption  of  fuel  has  been  brought  down  to  2^2  Ibs.  per  I.  H. 
P.  per  hour,  but  the  limit  attainable  is  still  far  ahead  of  general 
achievements  in  practice.  How  much  room  remains  for  improve- 
ment is  shown  by  the  exceptional  results  obtained  by  special  care  and 
design  in  certain  recent  constructions,  such  as  the  fast  torpedo  boats 
and  high  speed  yachts  of  the  period,  as  well  as  by  new  inventions 
destined  in  course  of  time  to  supersede  the  present  standard  com- 
pound of  two  cylinders,  just  as  the  latter  has  displaced  the  simple 
expansion  machine. 

The  U.  S.  Coast  Survey  steamer  Hassler,  designed  by  Mr.  C.  E. 
Emery,  affords  an  illustration  of  the  best  results  yet  accomplished  in 
American  sea-going  service  with  two  cylinder  compounds.  The 
Hassler  is  151  ft.  long,  24^  ft.  beam  and  loft,  draft.  Engines  have 
cylinders  of  18  and  28  in.  diameter  by  28  in.  stroke,  indicating  125 
H.  P.,  with  steam  at  75  Ibs.  pressure.  At  a  speed  of  7  knots,  the 
consumption  of  coal  was  1.87  Ibs.  per  horse  power  per  hour. 

The  following  up  of  the  ideas  upon  which  the  two  cylinder  com- 
pound has  been  developed,  has  led  very  recently  to  the  introduction 
of  triple  and  even  quadruple  expansion  machines.  In  these  the  total 
range  of  expansion  is  divided  between  three  and  four  cylinders. 
The  triple  expansion  is  not  to  be  confounded  with  the  three-cylin- 
der compound,  in  which  the  exhaust  steam  from  the  high-pressure 


Theory  of  the  Steam  Engine.  23 

cylinder  is  allowed  to  expand  simultaneously  in  two  low-pressure 
cylinders  with  equal  initial  pressure.  The  latter  differs  from  the  two^ 
cylinder  compound  only  in  arrangement,  the  work  of  low  pressure 
being  accomplished  in  two  chambers  instead  of  one.  In  the  triple 
expansion  engine,  the  exhaust  is  led  into  a  second  or  "intermediate" 
cylinder,  partly  expanded,  and  its  exhaust  again  into  a  third  cylinder, 
where  the  expansion  is  completed.  Despite  the  multiplication  of 
parts,  a  material  benefit  arises  from  this  further  subdivision.  Jn  the 
steam  yacht  Isa,  engined  by  Messrs.  Douglas  &  Grant,  of  Kircaldy, 
Scotland,  a  working  pressure  of  i2olbs.  is  maintained,  the  cylin- 
ders being  10,  15  and  iSin.  diameter,  and  24  in.  stroke.  They 
indicate  200  H.  P.  on  300  Ibs.  coal  per  hour,  or  i  H.  P.  for  i^lbs. 
of  fuel.  Observations  made  upon  some  of  the  latest  British  trading 
steamers  have  shown  a  saving  of  19.5  per  cent.,  and  an  increase  of  6 
per  cent,  in  speed  by  the  use  of  triple  expansion,  and  no  Ibs.  pres- 
sure over  ordinary  compounds  with  90  Ibs.  pressure,  sustaining  the 
conclusions  set  forth  above  and  pointing  out  the  direction  to  be  pur- 
sued for  further  improvement. 

Among  the  most  recent  examples  in  triple-expansion  engines,  are 
those  of  the  steam  yacht  Gladiator,  built  by  Messrs.  Ramage  & 
Ferguson  of  Scotland,  the  plans  of  which  are  taken  from  Engineering. 

The  vessel  is  113  ft.  keel  aforerake,  with  20  ft.  beam  and  13  ft. 
depth  moulded,  and  is  fitted  with  a  Bevis  patent  feathering  propeller, 
driven  by  a  set  of  triple-expansion  engines.  The  diameters  of  the 
cylinders  are  9%  in.,  15  in.,  and  24^  in.,  with  1 8  in.  stroke.  They 
are  supplied  with  steam  at  a  working  pressure  of  150  Ibs.  per  square 
inch,  by  a  steel  cylindrical  tubular  boiler  8ft.  6  in.  in  diameter  by 
7  ft.  9  in.  long,  with  one  of  Fox's  patent  corrugated  furnaces.  This 
boiler  has  a  firegrate  area  of  15  sq.  ft.,  and  500  sq.  ft.  of  heating  sur- 
face. The  particulars  of  the  various  pipes  shown  and  numbered 
in  the  views  are  given  in  the  subjoined  table. 


Theory  of  the  Steam  Engine. 


LIST  OF  PIPES. 

Steam  Pipes: 

No.  Material.     Bore,  in.  B.  W.  G.* 

•  i     Main  steam Copper  2j^  8 

2  Steam  to  starting  valves "  12 

3  donkey "  10 

4  whistle 10 

5  ' '     and  water  to  gauges "  j/jf  9 

6  to  windlass "  12 

Exhaust  Pipes: 

7  Main  waste  steam "  4*^  16 

8  Bottom  blow-off "  i^  9 

9  Surface "  i^  9 

10  Exhaust  from  donkey "  i^  16 

Water  Pipes: 

11  Circulating  suctions "  3^  12 

12  discharge "  3^  12 

13  Air  pump                    "  3^  I2 

14  Bilge  discharge  overboard i  y^  14 

15  Main  feed  discharge "  ii^  g 

16  suction  from  hot-well "  i*£  14 

17  Donkey                            sea  and  bilge "  i#  14 

18  hot-well "  i^  14 

19  discharge  to  three-way  cock "  i$  14 

20  boiler "  ij£  g 

21  on  deck "  i}£  14 

22  to  condenser "  i^  14 

23  overboard '*  ij%  14 

24  Fireman's  water  service "  1 1£  16 

25  Drain  pipe  from  safety  valves "  i  15 

Bilge  Pipes: 

26  Circulating  bilge  suction Lead  2 

27  Donkey  suction  from  bilge "  l^ 

28  Suction  from  aft  hold "  i^ 

29  engine-room "  i  ^ 

30  "             fore  hold "  i|| 


*  B.  W.  Gr.=  Birmingham  Wire  Gauge. 


On  trial,  during  a  strong  breeze  and  with  a  considerable  sea  on,  a 
speed  of  8%  knots  was  attained,  the  engines  indicated  162  horse- 
power at  145  revolutions.  The  power  being  equally  distributed  be- 
tween the  cylinders  being  for  the 

Horse-Power. 

High-pressure  cylinder 54 

Intermediate-pressure  cylinder 53.66 

Low-pressure  cylinder * 54-43 

162.09 


FIG.   5. — ENGINES  AND  BOILERS  OF  STEAM  YACHT  GLADIATOR.     FORE  AND 

AFT  ELEVATION. 


26  Theory  of  the  Steam  Engine. 

The  best  general  practice. of  the  day  has  brought  us  down  to  some- 
thing over  two  pounds  of  coal  per  horse  power  per  hour.  This  is, 
however,  only  one-tenth  the  power  derivable  from  the  fuel  were  all 
its  heat  fully  utilized,  nine-tenths  being  absolute  waste,  which  never 
performs  service  in  driving  the  machinery.  The  losses  can  be 
divided  as  70  per  cent,  of  heat  rejected  in  the  exhaust  steam,  20  per 
cent,  lost  by  conduction  and  radiation  and  the  faults  of  practice,  only 
10  per  cent,  remaining  for  actual  utilization.  Thirty  per  cent,  of  the 
heat  generated  in  the  furnace  is  lost  by  passing  out  at  the  chimney. 
Of  the  remainder  which  enters  the  engine  20  per  cent,  is  all  of  which 
we  can  hope  to  save  any  portion  by  improvements  in  design  and  con- 
struction of  the  engine  itself.  In  this  light,  even  the  best  practice  is 
exceedingly  faulty  and  wasteful.  Higher  results  within  the  20  per 
cent,  mentioned  are  to  be  sought  in  pressures,  expansion  rates  and 
piston  speeds,  of  which  we  have  as  yet  scarcely  any  conception, 
unless  an  entire  revolution  in  the  application  of  the  heat  generated 
in  the  furnace  is  a  discovery  destined  to  radically  displace  the 
general  procedure  with  which  the  engineering  world  is  at  present 
acquainted. 

Special  instances  of  great  economy,  as  things  go,  effect  a  consider- 
able saving  upon  more  general  practice,  but  even  these  instances  are 
far  from  approaching  the  theoretically  possible  attainments. 

As  far  back  as  1823,  Jacob  Perkins,  a  native  of  Newburyport, 
Mass.,  who  in  later  years  took  up  his  residence  in  London,  England, 
experimented  with  a  copper  boiler,  the  sides  of  which  were  3  in. 
thick,  the  safety  valves  being  loaded  to  550  Ibs.  per  square  inch. 
In  1827  he  had  attained  a  working  pressure  of  800  Ibs.,  but  exper- 
ienced much  difficulty  in  lubricating  at  the  great  heat  of  such  high 
steam,  the  oils  charring  and  decomposing.  Finally  this  was  over- 
come by  substituting  rubbing  surfaces  of  a  peculiar  alloy  requiring 
no  lubrication.  He  also  cut  off  steam  at  one-eighth  the  stroke. 
Pressures  of  1400  and  even  2000  Ibs.  were  essayed.  Concerning 
these  remarkable  and  vital  investigations,  Stuart,  in  describing  the 
work  of  Perkins,  most  truthfully  comments: 

"  No  other  .mechanic  has  done  more  to  illustrate  an  obscure  branch 
of  philosophy  by  a  series  of  difficult,  dangerous  and  expensive  ex- 


C*7] 


28 


Theory  of  the  Steam  Engine. 


periments;  no  one's  labors  have  been  more  deserving  of  cheering 
encouragement,  and  no  one  has  received  less.  Even  in  their  present 
state  his  mechanism  bids  fair  to  introduce  a  new  style  into  the  pro- 
portions, construction  and  form  of  steam  machinery." 


FIG.  7. — GLADIATOR:    CROSS  SECTION  THROUGH  ENGINE-ROOM. 

That  Perkins  was  far  ahead  of  his  time,  far  ahead  even  of  the 
present  time,  and  that  he  was  the  pioneer  of  future  developments 
looking  forward  to  something  like  an  approach  of  practice  to  theory 
in  steam  engine  performance,  cannot  be  questioned,  but  is  receiving 
stronger  proof  from  day  to  day.  When  his  keen  perceptions  and 


Theory  of  the  Steam  Engine. 


29 


zealous  labors  shall  have  been  fully  appreciated,  the  world  will  be 
the  great  gainer,  and  possibly  will  not  fail  to  recognize  the  genius 
which  piloted  at  a  single  bound  the  fresh  advance  the  engineering 


FIG.  8. — GLADIATOR:     CROSS  SECTION  THROUGH  FIRE-ROOM. 


world  is  now  tardily  following  in  a  modest  way.  The  investigations 
of  the  elder  Perkins  have  been  pursued  by  his  sons,  and  through  them 
have  compelled  at  least  passing  attention  and  partial  recognition,  the 
consumption  of  coal  having  been  reduced  to  i^  Ibs.  The  gradual 
introductions  of  triple  and  even  quadruple  compounds  and  boilers 


30  Theory  of  the  Steam  Engine. 

belonging  to  the  "  pipe  "  or  "sectional"  variety  for  withstanding 
great  pressures  are  only  so  many  steps  on  the  road  already  practically 
exploited  by  the  Perkins  engine  and  boiler. 

The  greatest  range  of  temperature  is  the  sum  and  substance  of 
theoretical  engine  economy.  The  rest  is  a  matter  of  mechanical 
device  for  cheaply  generating  and  safely  containing  high  steam  and 
utilizing  it  with  the  least  loss  in  the  machinery  of  transmission. 

To  secure  the  greatest  range  of  temperature  the  highest  initial 
pressure  must  be  introduced  into  the  cylinder  and  the  steam  allowed 
to  expand  to  the  utmost  to  part  with  .all  its  heat  energy.  But  there 
is  a  limit  in  economy  to  which  expansion  can  be  carried,  a  fact  not 
generally  understood  or  recognized. 

The  power  remaining  near  the  end  of  a  stroke  from  which  steam 
has  been  cut  off  at  a  very  small  fraction  of  the  stroke  will  have 
declined  so  rapidly  with  the  simultaneous  decrease  in  temperature 
that  it  will  be  of  little  service.  But  as  this  limit  is  constantly  pushed 
further  with  an  increase  of  initial  pressure,  it  follows  that  the  best 
results  will  be  obtained  from  the  highest  pressure  to  start  with,  and 
expansion  to  the  extreme  economical  limit  of  that  pressure. 

The  theory  of  the  steam  engine  is  now  fairly  well  understood,  and 
attention  is  being  focussed  upon  the  mechanical  appliances  with 
renewed  energy  and  clearer  perception,  so  that  we  may  reasonably 
expect  appreciable  advance  in  saving  some  of  the  ninety  per  cent,  of 
heat  energy  now  wasted,  through  the  introduction  of  improved  or 
entirely  novel  methods.  When  the  coal  per  I.  H.  P.  per  hour  is 
measured  by  ounces  instead  of  pounds,  the  steam  engine  will  return 
to  us  in  service  a  reasonable  proportion  of  the  energy  stored  in 
nature's  great  reservoir  of  combustibles  instead  of  the  nominal  quan- 
tity at  our  command  at  present. 


II. 

BOILER     EFFICIENCY. 

THE  principles  involved  in  designing  boilers  are  few  and  simple. 
Although  numerous  attempts  have  been  made  to  reach  improved 
results  by  varying  arrangements,  the  best  boilers  are  nearly  all  equal 
in  efficiency  and  by  no  means  superior  to  some  of  the  earlier  types. 
The  modern  cylindrical  return  tubular  boiler,  now  very  common  in 
yachts,  is  not  even  quite  as  efficient  as  the  old-fashioned  patterns 
with  rectangular  fire  boxes,  long  ago  abandoned.  The  cylindrical 
form  has,  however,  become  a  necessity  with  the  high  pressures  now 
customary,  and  represents  less  weight  for  its  power,  there  being  a 
great  saving  in  bracing  and  staying  over  weaker  forms. 

The  requisites  in  a  good  boiler  are  the  most  thorough  combustion 
of  fuel  in  the  fire  box  without  dilution  of  the  products  of  combus- 
tion by  excess  of  air  and  consequent  cooling.  This  implies  as  high 
a  temperature  as  possible  in  the  fire  box.  Heating  surfaces  should 
be  so  arranged  as  not  to  check  the  draft,  and  yet  take  up  all  the  avail- 
able heat  from  the  gases,  which  is  the  temperature  in  the  furnace 
less  the  temperature  of  the  gases  escaping  at  the  chimney  required 
to  produce  draft.  The  grate  surface  should  be  sufficient  to  provide 
for  the  consumption  of  the  fuel  necessary  to  develop  the  heat  or 
power  intended. 

The  mechanical  considerations  which  should  govern  are  strong 
and  cheap  construction,  with  every  part  accessible  for  cleaning  pur- 
poses, no  parts  weaker  than  others,  and  the  least  opportunity  for 
local  corrosion,  scaling  or  burning. 


32 


Boiler    Efficiency. 


For  complete  combustion  the  supply  of  air  should  be  ample  through 
the  grate,  and  its  intermixture  with  the  fuel  facilitated.  For  high 
temperature  in  the  furnace,  the  air  supply  must  not  exceed  that 
required  for  perfect  combustion.  The  greater  the  range  of  temper- 


B' 


FIG.  9. — RETURN  TUBULAR  BOILER  WITH  DOUBLE  FURNACES. 


A.  Shell  of  boiler. 

B.  Furnaces  with  doors  and  draft. 

C.  Ash  pits  or  ash  pans. 

D.  Tubes  through  which  gases  return.     (The 

uptake  is  omitted.) 


E.  Steam  dome  for  collecting  dry  steam. 

F.  Stays  to  combustion  chamber. 

G.  Manholes  for  access  to  interior. 
H.  Longitudinal  stays. 


ature  between  furnace  and  chimney,  the  greater  the  amount  of  heat 
available  for  transfer  to  the  water.  If  the  temperature  in  the 
chimney  approaches  that  in  the  furnace,  there  will  evidently  be  little 
heat  to  give  off  to  the  heating  surface.  Similarly,  if  the  heat  in  the 
furnace  be  cooled  down  by  the  admission  of  too  much  air,  efficiency 


Boiler    Efficiency. 


33 


will  be  destroyed.  The  disposition  of  the  heating  surface  in  tubes 
and  plates  should  not  interfere  with  free  circulation  of  the  water  in 
the  boiler,  and  the  steam  must  be  withdrawn  from  the  boiler  as  free 
from  vapor  as  possible.  The  cold  feed  water  should  enter  where 
the  gases  are  coolest,  to  prevent  needlessly  cooling  down  the  heated 
surfaces. 

In  practice,  the  temperature  escaping  at  the  chimney  has  been 
reduced  to  300  deg.  Fahr.  without  checking  the  draft,  and  an 
efficiency  of  75  to  80  per  cent,  of  the  theoretically  possible  has  been 
attained.  The  Clyde  boiler  is  in  common  use  for  steam  yachts,  most 
frequently  with  a  single  furnace.  It  is  of  the  return  tubular  variety, 
and  built  to  the  following  dimensions: 


FIG.  10. — CLYDE  BOILER.     BUILT  BY  CHAS.  P.  WILLARD  &  Co.,  CHICAGO. 


Length 
In. 

Diam. 
In. 

Diam. 
Furnace 

Tubes 
No. 

Tubes 
Diam. 

Dome 
Diam. 

Dome 
Height. 

Sq.    ft. 
Heating 

Surface. 

Engine. 

Weight  of 
Boiler. 

42 

30 

15 

40 

Itf 

14 

9 

42 

4^X   5 

775lbs. 

44 

36 

18 

56 

i$* 

16 

IO 

62 

5     X   7 

noolbs, 

48 

36 

IS 

56 

i* 

16 

IO 

80 

6X8 

i2oolbs. 

50 

40 

18 

70 

1/2 

18 

12 

90 

6^X  8 

iSoolbs. 

56 

44 

20 

52 

2 

20 

14 

105 

7     X  8 

iSsolbs. 

68 

48 

22 

68 

2 

22 

16 

170 

8     Xio 

2200lbs. 

34 


Boiler    Efficiency. 


Sectional  or  pipe  boilers  are  now  receiving  that  attention  which  k 
their  due  in  connection  with  very  high  pressures,  and  the  question 
of  their  generation  with  safety.  It  is  not  too  much  to  expect  that  the 
time  is  not  far  distant  when  the  shell  boiler  will  be  entirely  given  up 


FIG.  ii. — THE  PERKINS  PIPE  OR  WATER  TUBE  BOILER. 


A.  Grate  bars. 

B.  Square  furnace  built  up  of  tubes. 

C.  Water-tubes  connected  by  pipe  at  ends. 

D.  Steam  drum. 


E.  Smokestack. 

F.  She.tiron  casing  filled  with  non-conductor. 

G.  Door  for  access  to  interior. 
H.  Furnace  door. 


Boiler    Efficiency.  35 

and  the  use  of  high  steam  freed  from  all  critical  danger.  The  pipe 
boiler  is  an  old  device,  the  utility  of  which  was  long  ago  recognized 
by  those  experimenting  upon  high  steam.  In  1831,  Jacob  Perkins 
patented  a  sectional  boiler  in  which  the  gratebars  were  composed  of 
tubes,  and  subsequently  used  tubes  only,  without  any  large  reservoir 
for  water  and  steam.  The  economical  performance  of  such  boilers 
with  like  ratio  of  heating  surface  to  grate  surface  is  equal  to  that  of 
the  best  boilers  of  the  shell  type.  Their  only  drawback  is  the  diffi- 
culty of  keeping  up  a  steady  supply  of  steam,  as  there  is  little  re- 
serve to  draw  upon.  But  this  is  now  being  met  by  special  devices. 

A  pound  of  pure  carbon  is  theoretically  capable  of  evaporating 
i5lbs.  of  water  from  boiling  point  of  212  deg.  In  practice  this 
is  not  reached  owing  to  the  compulsory  loss  of  temperature  passing 
out  of  the  chimney  to  produce  draft  enough  to  draw  air  into  the 
furnace.  The  draft  is  consequent  upon  the  heat  of  the  escaping 
gases  making  them  lighter  than  the  air  and  disturbing  balance  by 
the  atmosphere  at  top  of  chimney  and  entrance  to  furnace,  the 
greater  pressure  at  the  ashpit  door  forcing  the  air  up  through  the 
grate  bars.  Part  of  the  combustible  gases  in  the  furnace  are  also 
carried  off  without  being  burnt  and  some  heat  is  also  lost  by  radia- 
tion, owing  to  imperfect  covering  of  exposed  metal  surfaces  with  non- 
conducting material,  such  as  felt,  asbestos  or  patent  preparations. 
In  marine  boilers  the  gasses  are  allowed  to  escape  at  the  chimney  at 
nearly  600  deg.  Fahr. 

The  evaporative  power  of  good  coal  is  13^2  compared  to  15  Ibs.  of 
water  for  pure  carbon.  Of  the  coal  burned  in  steam  boilers,  thirty  per 
cent,  of  evaporative  power  is  lost  as  already  explained,  and  frequently 
more.  Seventy  per  cent,  is  all  the  energy  sent  to  the  cylinder  less 
further  losses  in  transmission.  Thus  actual  trial  shows  that  instead 
of  evaporating  15  Ibs.  of  water,  the  standard  for  pure  carbon,  the 
energy  sent  to  the  cylinder  per  pound  of  coal  is  only  about  9^  Ibs. 
of  water  evaporated,  and  8  Ibs.  would  oftener  be  the  truth. 

Theoretically  12  Ibs.  of  air  is  enough  to  consume  i  Ib.  of  coal,  but 
in  practice  15  to  25  Ibs.  are  required,  owing  to  imperfect  mixing  with 
the  fuel  and  losses  through  the  draft.  The  product  of  combustion 
is  carbonic  acid  gas.  Soft  or  bituminous  coal  needs  more  air  above 


36  Boiler     Efficiency. 

the  furnace  bars  than  hard  coal  having  a  higher  per  centage  of  car- 
bon, as  the  hydrogen  liberated  from  soft  coal  takes  up  a  larger 
amount  of  oxygen  in  the  process  of  combustion  than  the  same  vol- 
ume of  carbon. 

A  small  volume  of  air  is  always  admitted  above  the  firebars  to  in- 
sure a  sufficient  supply  for  the  escaping  gases.  Totaj  area  of  such 
openings  may  be  from  3  to  5  in.  per  square  foot  of  grate.  Means 
must  be  supplied  for  regulating  the  area  opened  according  to  the  fuel 


FlG.    12. — BORDENTOWN     "DOGHOUSE"     BOILER. 

38  in.  face  ;  38  in.  high  ;  48  in.  long :  50  tubes  2  in.  diam.  and  41  in.  long  ;  dome  20X20  in.;  working 
pressure  125  Ibs.;  weight  900 Ibs.;  engine  6X8  in. 

and  draft.  Too  large  a  supply,  as  in  case  of  throwing  the  door  open, 
"dampens"  or  cools  down  the  fire  by  absorbing  the  heat  given  out 
from  the  fuel. 

Forced  draft  has  lately  received  attention.  The  stoke  hole  is  closed 
and  an  artificial  pressure  produced  by  means  of  a  "blower"  or  rapid- 
ly revolving  fan,  promoting  combustion  and  the  transmission  of  a 


Boiler    Efficiency.  3  7 

greater  amount  of  heat  to  the  water  in  the  boiler  for  sustaining  a 
higher  pressure  or  the  more  rapid  supply  of  steam.  Another  method 
is  to  close  up  the  fire  front  and  blow  in  air  from  a  fan  at  the  extrem- 
ity of  a  tube  connecting  with  the  ashpit.  As  might  be  expected,  the 
additional  power  so  gained  is  obtained  at  corresponding  loss  in  econ- 
omy, as  the  process  of  combustion  is  forced  too  rapidly  to  be  thorough, 
and  the  loss  at  the  chimney  end  is  increased.  With  an  air  pressure 
in  the  stoke  room  equal  per  square  inch  to  the  weight  of  a  column  of 
mercury  6  in.  high,  the  evaporative  power  of  the  locomotive  boiler  of  a 
torpedo  boat  was  found  to  be  about  doubled  and  the  consumption 
of  coal  likewise. 


FIG.  13. — STURTEVANT  BLOWER. 

In  recent  steamers  built  for  the  merchant  service,  special  arrange- 
ments of  the  furnaces  have,  however,  demonstrated  the  feasibility  of 
applying  forced  draft  with  a  view  to  economy,  the  fuel  being  more 
thoroughly  consumed  and  giving  higher  results  per  pound  than  when 
relying  upon  natural  draft  only.  Such  prominence  has  this  question 
of  artificial  draft  assumed  of  late  that  we  may  predict  with  confidence 
the  universal  application  of  the  blast  to  marine  boilers  in  the  near 


38  Boiler    Efficiency. 

future.  Yacht  owners  in  America  have  the  opportunity  to  lead  the 
way  in  this  as  in  other  improvements  instead  of  following  tardily  in 
the  wake  of  the  foreign  merchant  marine. 

For  5  sq.  ft.  of  grate  surface  the  diameter  of  the  inlet  for  the  blower 
should  be  5  in.  and  the  outlet  4  in.  For  10  ft.  of  grate,  the  inlet  and 
outlet  are  7^2  in.  At  2000  revolutions  per  minute,  looocub.  ft. 
of  air  will  be  forced  into  the  furnace  at  an  expenditure  of  ^  H.  P. 
For  20 sq.ft.  of  grate,  the  inlet  and  outlet  are  10^2  in.,  and  at  1500 
revolutions,  2000  cu.  ft.  of  air  will  be  forced  into  the  furnace  at  an 
expenditure  of  1^2  H.  P. 

Grate  surface  is  the  starting  point  for  apportioning  the  rest  of  the 
boiler.  With  a  given  area  of  grate,  a  given  amount  of  fuel  can  be 
burned,  and  the  utilization  of  the  heat  determines  the  other  data  of 
the  design.  Long  grates  are  difficult  to  fire,  hence  the  length  is 
usually  restricted  to  i^  to  2  times  the  diameter  of  the  furnace.  The 
width  of  the  grate  determines  the  diameter  of  the  furnace  in  the  first 
place.  From  14  to  20  Ibs.  of  coal  can  be  burnt  per  square  foot  of 
grate.  The  horse-power  desired  with  the  presumed  efficiency  of  the 
boiler  enable  us  to  settle  upon  the  area  of  grate  by  allowing  say  one- 
tenth  of  a  square  foot  of  grate  to  each  1.  H.  P.  The  area  of  heating 
surface  must  be  from  20  to  30  times  that  of  the  grate.  For  free 
draft  the  cross  section  of  the  tubes  contributing  to  the  heating  sur- 
face should  be  about  one-seventh  that  of  the  grate  area.  From  these 
considerations  the  length  and  number  of  tubes  required  is  determined 
after  settling  upon  their  diameter.  There  is  much  latitude  in  the 
proportions  given  above,  and  the  preferences  of  builders  in  construct- 
ing boilers  of  varying  arrangement  and  detail  establish  the  practice 
in  each  shop. 

Numerous  small  tubes,  while  affording  more  surface,  interfere  with 
free  draft  and  are  difficult  to  clean,  besides  causing  violent  ebullition 
and  foaming  known  as  "priming"  when  placed  too  close.  The  rule 
is  to  give  tubes  a  diameter  equal  to  one-twenty-fourth  to  one-thirtieth 
their  length,  with  ^  to  TK  mcn  clearance  between  them.  In  short 
boilers,  such  as  the  popular  return  tubular,  in  which  the  furnace  is 
situated  under  the  tubes,  a  "  combustion  chamber  "  is  built  at  the  end 
opposite  the  door,  to  further  the  proper  burning  of  the  gases.  This 


Boiler     Efficiency. 


39 


chamber  is  in  reality  only  an  extension  of  the  firebox  without  any 
grate. 

In  long  boilers  of  the  locomotive  type,  in  which  the  tubes  lead 
directly  from  the  firebox,  such  chambers  are  omitted,  as  heat  enough 
passes  into  the  tubes  to  complete  combustion  in  them,  and  the  same 
applies  to  vertical  tubular  boilers.  The  return  tubular  boiler  is  pre- 
ferred for  yachts,  owing  to  the  small  fore-and-aft  space  occupied, 
but  the  performance  of  the  locomotive  boiler  is  a  trifle  better,  the 
weight  and  cost  both  less,  as  no  combustion  chamber  has  to  be  built 
and  stayed.  For  forced  draft  this  type  is  especially  well  adapted. 


FIG.  14. — LOCOMOTIVE  BOILER. 


Fire  door. 
Furnace  or  firebox. 
Grate  bars. 
Tubes. 


E.  Uptake. 

F.  Smokestack. 


G.  Steam  dome. 

H.  Ashpit. 

K.  Crown  sheet  of  furnace. 

L.  Water  level. 

W.  Water-legs  surrounding  firebox. 


The  crown  sheet  of  the  firebox  is  a  very  efficient  heating  surface,  but 
has  the  drawback  of  suffering  from  expansion  and  contraction  and 
the  liability  to  being  left  bare  of  water  in  a  rough  sea.  "Compen- 
sating" stays  to  the  crown  sheet  and  dash  plates  as  well  as  keeping 
the  crown  lowest  at  the  door  obviate  these  troubles.  The  locomotive 
boiler  has  also  the  advantage  of  lying  low  in  the  vessel.  As  the  size 
decreases,  return  tubular  boilers  rapidly  lose  in  efficiency  and  are 


Boiler    Efficiency. 


costly  and  heavy.  For  small  launches,  the  vertical  tubular  boiler  is 
in  universal  use  in  America.  It  can  be  considered  as  a  locomotive 
boiler  set  on  end,  economizing  fore-and-aft  space. 

This  style  of  boiler  will  be  understood  from  the  annexed  illustra- 
tion and  dimensions,  representing  the  practice  of  Chas.  P.  Willard  & 
Co.,  of  Chicago,  111. 


FIG.  15. — VERTICAL  TUBULAR  LAUNCH  BOILER. 

It  will  be  noticed  that  the  flues  are  completely  submerged,  though 
in  other  boilers  of  the  kind  they  are  run  up  into  the  head,  the  gases 
discharging  into  an  uptake  above  the  boiler  shell  proper. 


Shell. 

Flues. 

Fire  Box. 

Diam. 

Height. 

No. 

Diam. 

Length. 

Height. 

Diam. 

Sq.   ft. 
Heating 
Surface. 

Engine. 

Weight  of 
Boiler. 

22 

36 

33 

I* 

12 

15 

14 

2O 

3X4 

33olbs. 

26 

48 

43 

2 

18 

IS 

22 

43 

4^X  5 

58olbs. 

30 

48 

68 

2 

18 

18 

26 

60 

5     X  7 

I04olbs. 

36 

50 

87 

2 

18 

18 

32 

92 

6X8 

I2OOlbs. 

40 

53 

99 

2 

18 

18 

36 

100 

6^X  8 

I53olbs. 

42 

S3 

116 

2 

20 

18 

38 

1  20 

7     X  8 

lyoolbs. 

48 

72 

160 

2 

24 

24 

42 

1  80 

8     Xio 

26oolbs. 

Boiler     Efficiency.  4 1 

Water  tube  boilers,  in  which  the  heated  gases  from  the  furnace 
pass  around  the  tubes  and  the  water  circulates  through  them,  have 
given  comparatively  high  results,  as  might  be  expected  from  their 
character.  Competitive  tests  made  between  the  horizontal  fire  tubular 
boiler  and  the  Martin  vertical  water  tubular  boiler  of  the  U.  S.  Navy, 
under  like  conditions  in  other  respects,  have  demonstrated  the 
superior  evaporative  powers  of  the  water  tubes.  In  1859,  a  board  of 
U.  S.  officers  reported  to  the  Navy  Department  that  in  respect  to 
weight,  facility  for  removing  scale,  and  evaporative  efficiency,  the 
water  tubular  system  had  an  appreciable  advantage,  but  that  in  the 
fire  tubular  arrangement  the  draft  could  be  forced  to  a  greater 


FIG.    16. — Fox's  MILD  STEEL  CORRUGATED  FURNACE  FLUE. 

extent,  of  course  at  a  sacrifice  in  fuel.  This  report  only  anticipated 
the  superior  efficiency  of  the  more  recent  styles  of  pipe  boilers,  in 
which  there  is  no  longer  any  difficulty  in  forcing  the  draft  as  desired. 

It  is  always  advisable  to  have  ample  boiler  power.  Small  boilers 
for  the  work  must  be  forced  beyond  their  economical  limit,  and  are 
short  lived. 

The  number  of  furnaces  is  governed  by  the  length  and  breadth  of 
grate,  the  diameter  of  furnaces  varying  from  2^  to  4ft.  In  boilers 
of  8  ft.  length  or  less,  one  furnace  is  the  custom.  Beyond  that  two, 
three  being  uncommon,  except  in  the  largest  yachts.  Double  fur- 
naces have  the  advantage  of  enabling  successive  cleaning  and  stok- 


42  Boiler    Efficiency. 

ing,  preserving  more  even  supply  of  steam  than  when  the  door  of  a 
single  furnace  is  thrown  open.  Fox's  corrugated  mild  steel  flues  are 
now  being  introduced  in  America  for  furnace  construction,  giving 
greater  strength  and  more  surface  for  weight  of  metal  than  the 
smooth  plate,  and  permitting  expansion  and  contraction  without 
stress  to  the  material.  A  thinner  plate,  and  therefore  better  con- 
duction, is  another  point  in  favor  of  the  Fox  flue.  The  large  steam 
yacht  Alva,  recently  launched  by  Messrs.  Harlan  &  Hollingsworth, 
of  Wilmington,  Del.,  for  Mr.  W.  K.  Vanderbilt,  is  fitted  with  four 
Fox  corrugated  furnaces  to  each  boiler. 

Fire  box  and  combustion  chamber  must  be  large,  the  latter  about 
the  size  of  the  furnace  in  return  tubular  boilers.  The  steam  space 
above  the  water  must  not  be  too  small,  and  a  large  evaporating  sur- 
face to  the  water  is  important,  to  promote  the  equal  generation  of 
steam  without  priming.  It  is  customary  to  place  the  top  row  of 
tubes  two-thirds  the  diameter  of  the  boiler  above  the  bottom.  A 
small  body  of  water  promotes  rapid  steaming,  but  endangers  the 
tubes  and  crown  sheet  from  exposure,  as  the  level  is  more  likely  to 
fall  too  low.  Steam  drums  are  attached  to  boilers  for  the  storage  of 
steam,  so  that  it  can  be  drawn  off  dry  to  the  cylinder,  free  from 
foam. 

In  respect  to  circulation,  draft,  steam  space,  small  bulk  of  water, 
ready  access  for  cleaning  tubes,  lightness,  small  space  occupied,  sim- 
plicity, facility  of  repairs,  cost,  and  above  all  safety,  the  pipe  or  sec- 
tional type  of  water  tube  boilers  is  superior  to  the  ordinary  style  of 
fire  tube  boilers.  The  proper  estimate  now  placed  upon  working 
with  the  highest  pressure  attainable  must  soon  lead  to  the  abandon- 
ment of  explosive  shell  boilers  carrying  large  volumes  of  steam  and 
water  and  the  general  introduction  of  pipe  or  coil  sections  in  their 
stead. 

In  regard  to  fuel  there  is  equal  opportunity  for  radical  improve- 
ment. The  present  dependence  upon  coal,  involving  great  bunker 
space,  dirt  and  expense  in  filling  up  and  in  stoking,  smoke  and  hot 
fire  rooms,  is  a  serious  drawback  to  steam  yachting.  The  adaptation 
of  petroleum  to  the  needs  of  the  boiler  furnace  has  in  recent  years 
made  some  progress,  though  efforts  in  that  direction  are  still  in  the 


Boiler    Efficiency.  43 

first  stages.  Reports  are  conflicting  and  unreliable,  but  enough  has 
been  learned  to  justify  earnest  application  in  the  search  for  practi- 
cally substituting  mineral  oils  for  coal. 

Naphtha  and  electricity  have  already  been  made  to  serve  in  small 
launches,  the  former  with  great  economy  in  all  respects,  both 
sources  of  power  doing  away  not  only  with  coal  as  the  fuel,  but  dis- 
pensing altogether  with  the  use  of  steam.  Whether  we  are  to  see  such 
novel  motors  successfully  devised  on  a  large  scale,  meeting  the  needs 
of  seagoing  yachts,  is  for  the  future  to  tell.  It  is  certain,  however, 
that  evolution  toward  high  pressure  pipe  boilers  and  petroleum  fuel 
is  the  manifest  destiny  of  marine  engineering  in  the  yachting  fleet  as 
long  as  steam  continues  to  be  the  medium  for  the  conveyance  of 
heat  energy.  There  are  many  yacht-owners  whose  wealth  and  posi- 
tion would  enable  them  to  serve  the  engineering  world  and  their 
ov:n  interests  by  intelligent  pursuit  of  the  issues  involved,  but  un- 
fortunately we  have  so  far  looked  in  vain  for  any  appreciation  on 
their  part  of  the  field  for  experiment  and  profit  which  lies  before 
them,  or  of  the  "moral  duty"  they  owe  to  the  community.  The 
yacht  owner  in  America  appears  to  understand  only  one  thing,  the 
speed  attained  by  his  vessel.  Beyond  this  he  seems  to  be  completely 
divorced  from  her  performances.  The  organization  of  the  American 
Yacht  Club  with  the  attendant  accumulation  of  data  and  interchange 
of  experiences  will  in  course  of  time  provide  impetus  to  well  directed 
ambition,  and  broad  profitable  results  to  the  engineering  world  will 
no  doubt  displace  the  petty  differences  among  owners  as  to  who  pos- 
sesses the  fastest  vessel,  regardless  of  how  that  speed  is  produced. 

It  lies  within  the  power  of  many  a  yacht  owner  to  further  experi- 
mental research  and  accumulate  precise  fundamental  data  which 
would  advance  the  impending  "revolution  "  in  boilers  and  fuel  in  one 
year  to  a  stage  it  will  not  reach  within  one  or  more  decades,  if  we 
must  continue  to  rely  upon  the  scattered  efforts  of  individual  builders 
whose  interests  are  as  often  against  innovation  as  they  are  in  favor  of 
locking  up  for  their  private  benefit  what  discoveries  they  make.  The 
trials  carried  out  upon  some  of  the  Herreshoff  yachts  and  torpedo 
boats  are  notable  instances  in  exception.  They  have  contributed 
much  to  the  stock  of  knowledge  concerning  pipe  boilers,  and  re- 


44  Boiler     Efficiency. 

moved  prejudice  from  the  public  mind,  as  the  tests  were  openly  con- 
ducted under  supervision  of  U.  S.  officers. 

Builders  and  owners  of  British  steam  yachts,  who  appreciate  such 
results  not  merely  for  the  maximum  rate  of  speed  attainable,  but  even 
more  for  the  economics  of  engine  room  performance,  have  also  lib- 
erally encouraged  accurate  examination  by  trial  upon  individual  ves- 
sels. Much  remains  to  be  done,  however,  in  the  way  of  systematic 
investigation  by  thoroughly  competent  authorities.  To  such  end  or- 
ganizations like  the  American  (steam)  Yacht  Club  now  possess  the 
material  and  wealth,  and  it  rests  with  them  to  lift  a  superficial  pastime 
to  the  dignity  of  practical  utility.  Let  us  hope  that  the  day  is  not 
far  distant  when  the  query  "  What  is  a  steam  yacht  good  for,  any- 
way?" will  no  longer  be  heard  in  the  land. 

The  advance  made  in  British  practice  should  promote  higher  aims 
in  American  steam  yachting,  for  it  must  be  confessed  that  we  are  still 
far  behind  our  cousins  abroad.  It  is  true  that  as  a  rule  our  yachts 
attain  a  higher  maximum  speed,  but  that  is  because  we  recognize 
only  that  one  quality,  while  British  steam  yachts  are  purposely  de- 
signed for  economical  and  distant  cruising  without  a  view  to  high  speed 
except  in  special  craft  constructed  solely  to  that  end.  While  our 
yachts  do  not  compare  favorably  with  British  practice  as  cruising 
vessels,  they  are  also  inferior  in  speed  to  the  fast  types  produced  by 
the  chief  European  nations. 

The  racing  speed  of  the  Atalanta,  built  in  1883  by  Messrs.  Cramp 
&  Sons,  of  Philadelphia,  is  ig/4  land  miles,  or  16^  knots,  and  her 
average  sea  speed  not  over  14  knots.  The  highest  speed  reached  by 
the  Herreshoff  boat  Stiletto  is  about  22  land  miles  or  19  knots,  as 
near  as  accurate  runs  have  been  made.  Both  of  these  yachts  were 
designed  and  engined  for  high  speed  vessels  in  which  no  limiting 
considerations  were  entertained,  and  their  coal  consumption  is  ap- 
proximately 2J/2  Ibs. 

Yet  we  find  abroad  that  the  Spanish  torpedo  boat  El  Destructor, 
built  in  1886  by  Messrs.  J.  &  G.  Thomson,  has  developed  the  re- 
markable speed  of  23  knots,  or  27  miles,  being  8  miles  faster  than 
the  Atalanta,  despite  the  much  greater  length  of  the  latter.  If  it  is 
argued  that  in  small,  light  constructions  like  a  looft.  torpedo  boat, 


Boiler    Efficiency.  45 

the  power  can  bear  a  much  higher  ratio  to  the  displacement  than  in 
a  larger  vessel  like  the  233  ft.  Atalanta,  we  have  only  to  turn  to  the 
Cunard  liner  Etruria  to  find  the  speed  of  the  Atalanta  greatly  ex- 
ceeded in  a  lar-ge  and  heavier  steamship  carrying  cargo.  It  is  evi- 
dent that  there  is  as  much  room  for  higher  results  in  speed  in  Ameri- 
can yacht  building  practice,  as  there  is  for  distant  cruising  economy, 
concerning  which  scarcely  a  single  example  as  yet  exists  in  Ameri- 
can waters.  At  a  recent  trial  of  a  twin  screw  torpedo  boat,  built  by 
Messrs.  Yarrow,  for  the  Italian  Government,  a  speed  of  24.96  knots 
— equal  to  28^2  miles  per  hour  was  obtained.  This  is  the  highest 
speed  ever  attained  by  any  description  of  craft. 

The  rapid  advance  made  in  economy  can  be  gathered  from  the 
most  recent  results,  which  support  the  position  here  taken,  that  in 
the  maximum  pressure  and  expansion  lies  the  solution  of  engine 
economy,  and  that  nothing  short  of  the  pipe  boiler  will  meet  the  de- 
mands for  the  pressures  of  the  near  future. 

The  triple  expansion  engine  now  bids  fair  to  displace  the  com- 
pound of  John  Elder,  for  it  may  already  be  considered  as  demon- 
strated that  the  tripple  expansion,  with  still  higher  initial  pressure, 
is  as  much  ahead  of  the  compound  as  the  latter  was  an  advance  upon 
the  single  expansion  cylinder  worked  by  comparatively  low  steam. 

The  first  triple  expansion  engine  was  fitted  by  Messrs.  Napier  &  Sons 
to  the  steamer  Aberdeen,  trading  from  London  to  Australia.  This 
was  only  a  few  years  ago.  Last  year,  almost  every  steamer  sent  out 
from  the  Clyde  was  fitted  with  engines  on  the  same  plan,  whether 
vertical  or  horizontal,  for  paddle  or  screw,  or  even  for  barges  and 
dredges.  Pressure,  of  course,  had  to  rise  in  proportion,  for  reasons 
previously  explained.  From  the  75  Ibs.  of  a  few  years  ago  the 
demand  rose  to  100,  120,  140  and  i6olbs.,  which  has  become  the 
common  working  pressure  for  triple  expansion.  But  even  this  does 
not  suffice,  for  Messrs.  Denny  &  Co.  have  in  hand  quadruple  expan- 
sion engines  for  both  paddle  and  screw  steamers,  the  working  pres- 
sure to  be  1 80  Ibs.  Similar  engines  fitted  to  the  steam  yacht 
Rionnag-na-Mara,  170  ft.  long,  developed  528  I.  H  P.  at  a  speed  of 
12  knots.  Steam  of  1 80  Ibs.  initial  pressure  was  expanded  twelve 
times,  giving  the  unequalled  economy  of  1/3  Ibs.  coal  consumption 


46  Boiler     Efficiency. 

per  horse  power  per  hour.  During  a  long  cruise  to  the  coast  of 
Norway,  with  steam  often  down  to  145105.,  the  consumption  of 
mixed  coal,  not  of  the  highest  quality,  did  not  exceed  1.45  Ibs.  Such 
results  are  far  ahead  of  the  best  American  practice.  The  tendency 
is  constantly  toward  higher  pressure  and  greater  expansion,  and  there 
is  nothing  in  the  latest  practice  to  indicate  that  the  limit  has  been 
approached.  Bearing  in  mind  the  experiments  of  Jacob  Perkins 
more  than  half  a  century  ago,  and  the  machinery  perfected  by  his 
sons  and  practically  tested  a  quarter  of  a  century  ago,  the  engineer- 
ing world  of  to-day  is  in  reality  going  ahead  by  catching  up  with 
pioneers  who  have  already  passed  away.  Cutting  off  at  half  and 
three-quarter  stroke  is  still  common  enough.  Messrs.  Denny  &  Co. 
have  got  it  down  to  one-twelfth,  but  Loftus  Perkins  has  expanded 
thirty-two  times  in  the  engines  of  the  steam  yacht  Anthracite.  It  is 
to  be  regretted  that  a  fresh  experimental  start  should  not  have  been 
taken  by  enlightened  yacht  owners  from  the  results  arrived  at  by 
Perkins,  instead  of  merely  following  in  the  wake  of  the  merchant 
service,  in  which  improvements  must  needs  go  slow,  owing  to  finan- 
cial limitations. 


III. 

BOILER    MOUNTINGS. 

THE  unequal  expansion  of  boiler  plates  is  the  chief  cause  of 
leakage  at  the  laps  and  rivets  about  the  bottom  of  the  shell. 
In  raising  steam  the  temperatures  at  top  and  bottom  differ  greatly, 
and  the  effort  made  by  the  rigid  shell  to  adapt  itself  to  the  unequal 
expansions  to  suit,  leads  to  strains  which  may  start  the  seams  or 
even  crack  the  plates  and  sheer  the  rivets.  With  steam  at  5olbs., 
investigation  upon  a  boiler  in  use  showed  a  temperature  of  300  deg. 
near  the  surface  of  the  water  and  50  deg.  at  the  bottom,  a  difference 
of  250  deg.  The  heated  portion  of  the  boiler  was  besides  several 
times  as  large  as  the  cooler  portion.  The  amount  to  which  an  i8ft. 
plate  will  expand  at  250  deg.  is  |4  in.  In  this  proportion,  the  top  of 
the  boiler  was  lengthened,  while  the  bottom  scarcely  expanded  at 
all,  hence  it  is  easy  to  understand  the  probable  strain  of  such 
unequal  treatment.  The  only  way  to  avoid  extreme  tension,  is  to 
promote  circulation  of  the  boiler  water  as  much  as  possible.  For 
this  purpose  the  hydrokineter  has  been  introduced  in  England  with 
marked  success  in  the  yachts  of  the  large  class.  This  attachment 
is  seldom  to  be  met  with  in  American  practice,  but  the  fact  that  by 
its  means  the  temperatures  at  the  top  and  bottom  of  the  boiler  have 
been  kept  within  20  deg.  of  one  another,  shows  its  efficiency.  This 
instrument  consists  of  three  nozzles  capping  one  another,  the  first 
having  a  flange  fitted  inside  on  the  bottom  of  the  boiler  shell.  Steam 
from  the  donkey  or  winch  boiler  is  admitted  by  a  valve,  and  as  it 
rushes  through  the  hydrokineter,  the  water  in  the  bottom  of  the  boiler 


48 


Boiler  Mountings. 


is  drawn  in  through  annular  openings  between  the  nozzles  and  pro- 
pelled as  a  jet  out  of  the  third  nozzle  with  considerable  force,  there- 
by setting  up  circulation  in  the  boiler  water. 

The  attachments  of  a  boiler  comprise  :  Safety  valve,  steam 
gauge,  water  cocks,  water  gauge,  salinometer,  feed  valves,  blow 
valves,  dry  pipes  and  stop  valves.  Uptake,  dry  combustion  cham- 
ber, blast,  damper,  whistle,  injector  and  funnel  may  also  be 
deemed  attachments.  In  yacht  boilers  the  combustion  chamber  is 
always  an  integral  part  of  the  construction.  The  accompanying 
diagrams  will  elucidate  the  parts  in  detail. 


FIG.  17. — RETURN  TUBULAR  BOILER,  U.  S.  NAVY  LAUNCH. 


C49l 


50  Boiler  Mountings. 


EXPLANATION    OF    DIAGRAMS. 

A.  Cylindrical   furnace,  within  the  cylindrical   shell  of  the  boiler.     It  is  supplied  with*  a  "fire 

front,"  containing  the  furnace  door,  F,  and  ash  pit  door,  G.  It  is  riveted  to  the  tube 
sheets,  T  S,  in  front  and  rear,  and  is  completely  surrounded  by  water  circulating  under 
the  ashpit  through  the  space  E. 

B.  Grate  bars,  with  fire  bridge,  C,  at  back,  to  retain  the  fuel.     This  bridge  is  lined  with  fire 

brick,  shown  by  the  diagonal  shading. 

D.  The  ash  pit. 

E.  Water  space  underneath  the  ash  pit. 

F.  Furnace  door,  supplied  with  lining  sheet  on  the  interior  and  holes  for  draft. 

G.  Ash  pit  door  or  damper. 

H.    Combustion  chamber,  built  at  back  of  furnace.     It  is  stay-bolted  to  back  of  outer  shell  as   at 
N.     The  gases  from  the  furnace  pass  into  this  chamber  for  further  mixture  and  combus- 
tion, and  thence  return  to  the  front  through  the  tubes  I,  as  indicated  by  the  arrow. 
I.     Fire  tubes  surrounding  the  furnace.     They  are  "expanded"  into  the  tube  sheets  at  each  end, 

the  front  ends  leading  into  the  uptake,  L,  thence  into  the  smokestack,  T. 
J.    Water  space  above  the  furnace. 
K.     Steam  space  above  the  water  level. 
L.    Uptake. 

M.    Steam  drum  or  dome,  flanged  and  riveted  to  the  boiler  shell.     The  latter  is  pierced  with  holes 
to  allow  the  steam  access  to  the  drum,  from  which  the  steam  is  taken  free  from  foam  by 
the  steam  pipe  P  on  top  of  the  drum.     The  dome  and  perforations  take  the  place  of  "dry 
pipes"  in  large  boilers  without  drum. 
N.     Tie  rods  between  ends  of  boiler  shell,  called  stays. 

O.     Exhaust  pipe  from  non-condensing  engine,  leading  into  smokestack,  T. 
P.     Steam  pipe  for  supplying  the  engine. 

Q.     Stop  valve  for  regulating  and  shutting  off  steam  supply  to  engine. 
R.     Safety  valve,  depending  upon  a  spring  for  its  resistance  to  pressure  from  below. 
S.     Spaces  for  non-conducting  covering  between  boiler  shell  and  external   wood  lagging  in  which 

the  boiler  is  encased. 
T.    Smokestack,  with  joint  for  lowering. 

U.     Steam  blast  from  drum  to  smokestack  to  increase  the  draft. 
V.    Door  to  uptake,  by  which  all  the  tubes  can  be  got  at  for  cleaning. 
W.     Independent  pump  for  feeding  the  boiler. 
X.     Steam  gauge,  for  indicating  pressure  within  the  boiler. 
Y.     Glass  water  gauge,  showing  height  of  water  in  boiler. 
Z.    Steam  valve  to  steam  end  of  independent  feed  pump. 
P  F.     Feed  suction,  for  supplying  water  to  the  pump. 
B  F.     Boiler  feed  pipe  from  pump. 
B  O.     Bottom  blow-off,  by  which  the  water  in  boiler  can  be  blown  out.     Also  for  filling  boiler 

when  cold,  owing  to  higher  level  of  sea  at  boat's  side. 

L  L.     Cast  iron  legs  to  boiler.     These  legs  are  bolted  down  to  the  boiler  keelsons. 
M  H.    Hand  hole  plates,  which  can  be  removed  to  clean  out  combustion  chamber. 
W  S.     Steam  whistle  in  top  of  drum. 
W  C.     Water  cocks,  for  testing  height  of  water  level. 
D  P.     Drip  pipe  from  water  cocks,  leading  into  bilge  of  boat. 


Boiler  Mountings.  51 

The  bolts  shown  on  top  of  boiler  are  for  hoisting  in  and  out  of 
boat.  This  boiler  is  suitable  for  a  launch  33  ft.  long,  8  ft.  beam  and 
3  ft.  9  in  draft.  The  shell  is  3  ft.  4^  in.  diameter  outside  ;  furnace 
2ol/>  in.  external  diameter,  the  plates  of  shell  and  furnace  being  %  in. 
thick,  as  also  the  tube  sheets.  There  are  60  return  tubes  3  ft.  1^2  in. 
long  and  2  in.  diameter  outside.  Area  of  grate  4.5  sq.  ft.,  heating 
surface  125  sq.  ft.  The  dome  is  20  in.  diameter,  14  in.  high.  Weight 
complete  2350  Ibs. 

SMOKESTACKS  are  proportioned  to  the  cross-sectional  area  of  tubes 
and  should  gradually  contract  to  meet  the  cooling  of  the  gases, 
although  in  practice  the  contraction  is  confined  to  the  uptake. 
Friction  would  limit  the  height  of  a  chimney,  but  the  fault  is  always 
the  other  way,  most  stacks  being  too  short  for  good  draft 

SAFETY  VALVES  are  made  in  great  variety,  differing  in  details  of 
design,  but  all  depend  upon  the  same  principles.  The  common  safety 


FIG.  20. — COMMON   SAFETY  VALVE. 

valve  is  shown  in  the  diagram.  For  loading  the  valve  lever  the 
measurements  are  made  from  the  fulcrum  F.  The  long  arm  is  the 
distance  from  F  to  center  of  weight  W,  and  the  short  arm  is  the  dis- 
tance from  F  to  vertical  center-line  of  the  valve-stem.  We  have 
from  the  principles  of  mechanics  the  formula  P/=  W  L,  in  which  P 
is  the  desired  pressure  under  the  valve  and  W  the  weight  hung  upon 
the  lever.  This  would  not  take  into  consideration  the  weight  of  the 


52  Boiler  Mountings. 

valve,  its  stem  and  the  lever,  for  which  allowance  must  be  made  in 
fixing  upon  W  or  its  distance  from  the  fulcrum  F.  By  removing  W 
and  attaching  a  spring  balance  at  end  of  lever  the  weight  of  the  gear 
itself  can  be  obtained,  which  must  be  subtracted. 


FIG.  21. — MARINE  POP  SAFETY  VALVE.     AMERICAN  STEAM  GAUGE  Co. 

Example :  A  safety  valve  is  6  in.  diameter  and  it  is  required  to 
blow  off  at  6olbs.  pressure  per  square  inch;  the  weight  W  is  175  Ibs., 
and  that  of  the  gear  120  Ibs.  The  short  arm  /  is  4  in.  Required  the 
distance  from  fulcrum  at  which  W  must  be  suspended.  The  area  of 
a  6  in.  circle  is  28.26  sq.  in.,  then 

L_[(28.26x6o)  — i2o]X4_36in 

175 
In  small  safety  valves,  springs  take  the  place  of  the  weight.     The 


Boiler  Mountings. 


53 


strength  of  the  spring  forcing  the  valve  into  its  seat  can  be  regulated 
by  screwing  a  nut  on  the  stem  up  or  down.  The  pressure  at  which 
it  blows  off  will  be  shown  by  the  steam  gauge.  There  should  be  a 
limit  to  the  compression  of  the  spring  by  the  nut,  to  prevent  "bottling 
\p"the  steam  beyond  the  regular  working  pressure  for  which  the 


FIG.  22. — BOURDON  STEAM  GAUGE. 

boiler  is  intended.  The  area  of  the  valve  should  not  be  much  less 
than  half  a  square  inch  per  square  foot  of  grate,  and  the  "  lift "  should 
be  equal  at  least  to  one-quarter  the  diameter.  The  escape  pipe 
should  have  an  area  equal  to  that  of  the  valve.  Spring  valves  are 
preferable  in  small  vessels,  as  the  weight  on  the  lever  variety  is  affect- 
ed by  the  rolling  of  the  vessel.  In  construction  the  valve  should  be 
simple  and  strong,  so  as  not  to  clog  or  have  free  passage  of  steam 


54 


Boiler  Mountings. 


obstructed  by  details  of  construction  Periodical  inspection  of  the 
boiler  will  necessitate  modifying  the  safety  valve  to  suit  the  increas- 
ing age  of  the  boiler.  Explosions  are  frequently  to  be  ascribed  to 
carrying  the  original  pressure  on  old  and  more  or  less  worn  out 
boilers. 

STEAM  GAUGES  in  general  use  on  board  of  yachts  depend  for  their 
action  upon  the  expansion  of  thin  metal  tubes  or  diaphrams  com- 
municating motion  to  the  index  arm  through  a  system  of  levers.  In 


BOURDON  STEAM  GAUGE — INSIDE. 


the  Bourdon,  for  example,  the  steam  is  admitted  through  a  pipe 
connected  to  a  circular  tube  of  oval  section.  As  pressure  increases, 
the  tendency  will  be  to  straighten  out  the  tube.  This  will  cause  the 
index  arrow  to  revolve  in  obedience  to  the  intervening  arc  and 
pinion.  The  dial  is  marked  off  by  the  manufacturer  from  com- 
parison with  a  standard  mercury  gauge.  Another  form,  such  as  the 
Utica  steam  gauge,  derives  its  action  from  the  expansion  of  light 
metal  plates  in  a  casing  or  drum,  the  corrugated  sides  of  which 
answer  vertically  to  increase  of  pressure.  The  motion  thus  obtained 
can  be  multiplied  by  a  system  of  levers. 


Boiler  Mountings. 


55 


The  steam  pipe  connecting  with  the  boiler  is  made  with  a  neck  or 
syphon  to  collect  water  which  will  act  as  a  cushion  between  the  live 
steam  and  the  working  parts  of  the  gauge.  A  cock  at  the  top  of 
the  bend  prevents  accumulating  too  much  water  by  occasional  atten- 
tion. This  whole  arrangement  is  shown  at  X  in  Fig.  19.  These 
gauges  are  sensitive  and  require  care.  They  should  be  cleaned 
from  time  to  time,  else  the  thickening  of  the  lubricants  or  stoppage 
of  passages  may  totally  deceive  the  engineer.  If  supplied  with  a 
blow-off  cock  on  top,  the  steam  can  be  turned  off  from  the  boiler 
and  the  cock  opened.  The  gauge  should  then  run  back  to  o.  If  it 


FIG.  23. — MERCURY  GAUGE. 


FIG.  24. — IMPROVED  MERCURY  GAUGE. 


does  not,  the  number  of  pounds  still  indicated  should  be  subtracted 
from  the  total  for  the  true  pressure.  Cocks  should  be  opened 
gradually  to  prevent  shock  to  the  mechanism. 

STANDARD  MERCURY  GAUGES  are  also  fitted  to  the  larger  class 
of  yachts.  They  depend  for  their  action  upon  the  weight  of  a 
column  of  mercury  contained  in  a  glass  tube.  The  simplest  form 
has  a  cross  area  of  i  sq.  in.  The  end  b  is  connected  with  the  boiler 
and  the  end  a  left  open,  the  neck  being  filled  with  mercury  to  some 
level  a  b.  The  weight  of  2  in.  of  such  a  column  equals  i  Ib.  Hence, 


56  Boiler  Mountings. 

if  the  steam  presses  down  the  mercury  i  in.  at  b,  it  will  rise  i  in.  in 
the  tube  a,  a  difference  of  2  in.  in  the  level.  A  scale  of  inches  at- 
tached to  a  will  indicate  the  number  of  pounds  pressure  in  boiler. 
The  area  of  the  tube  need  not  be  i  in.,  but  can  be  reduced  to  any 
fraction,  providing  the  area  exposed  to  the  steam  is  reduced  in  the 


FIG.  25. — SAFETY  COMBINATION  GAUGE.     AMERICAN  STEAM  GAUGE  Co. 


Boiler  Mountings.  57 

same  degree.  A  small  tube  prevents  oscillation  of  the  mercury. 
The  length  of  tube  a  would  become  impracticable  for  high  pres- 
sures, and  must  be  kept  down  by  the  intervention  of  compensating 
pistons. 

In  Fig.  24  is  shown  the  open  top  gauge  devised  by  Chief-Engineer 
A.  S.  Greene,  U.  S.  Navy.  In  a  casting  made  up  of  layers  a  piston 
is  introduced  with  the  small  area  C  exposed  to  the  steam  end  and 
the  large  area  D  to  the  scale  end.  A  small  descent  in  the  tube  A 
counterbalances  a  large  steam  pressure  owing  to  the  excess  in  area 
of  piston  C  over  that  of  tube  A,  and  a  still  smaller  ascent  takes  place 
in  the  scale  tube  B,  owing  to  excess  of  piston  D  over  C.  In  this 
way  the  scale  tube  is  kept  down  to  convenient  height. 

WATER  GAUGES  are  tapped  at  proper  heights  into  the  boiler  shell 
and  secured  with  nuts  on  inside.  They  indicate  the  water-level  and 
comprise  a  glass  measuring  tube  and  a  series  of  three  cocks,  both 
sets  being  imperative  as  a  check  upon  one  another,  for  low  water  is 
a  very  serious  matter  and  the  most  prolific  cause  of  explosions.  If 
the  level  were  to  fall  below  the  tubes  or  crown  sheet  of  furnace,  the 
iron  would  quickly  be  brought  up  to  red  heat  and  then  burnt,  or 
warp  permanently  out  of  shape.  If  the  feed  be  speeded  up,  the 
sudden  contact  of  cold  water  with  the  hot  iron  causes  the  water  to 
flash  into  steam,  rending  the  boiler  to  pieces.  The  glass  gauge  is 
fitted  with  a  stop  cock  at  each  end,  so  that  it  can  be  shut  off  from 
the  boiler,  and  a  broken  tube  replaced.  There  is  also  a  blow-off 
cock  at  the  bottom  for  drawing  off  the  water  occasionally  so  that 
upon  refilling  from  the  boiler  it  may  be  noted  whether  the  glass 
measures  uniformly  and  is  not  stopped  up.  In  dark  stoke  rooms,  a 
light  should  be  on  hand  for  correctly  noting  the  level.  The  water 
cocks  are  three  in  number,  so  placed  that  the  upper  one  should  show 
steam,  the  center  cock  steam  and  water  from  about  water  level,  and 
the  lower  one  always  water  only.  It  is  the  duty  of  the  engineer  to 
examine  by  these  so  frequently  that  the  level  shall  never  descend 
below  the  third  cock. 

FUSIBLE  PLUGS  are  further  safeguards  against  low  water,  and 
ought  to  be  fitted  to  all  boilers.  The  plug  consists  of  a  hollow  brass 
socket  screwed  into  the  crown  sheet  of  the  furnace.  A  smaller 


Boiler  Mountings. 


socket  is  screwed  into  the  fixed  one  and  a  hole  through  the  small 
one  filled  with  an  alloy  of  lead  and  copper  which  melts  at  compara- 
tively low  temperature.  When  the  water  level  falls  below  the  level 
of  the  plug,  the  alloy  melts  and  the  steam  escapes  into  the  furnace, 
giving  warning  and  dampening  the  fire.  A  spare  plug  can  then  be 
inserted  after  cooling  down  and  the  boiler  refilled.  The  plug  needs 
watching  to  prevent  covering  by  scale  and  should  be  renewed  occa- 
sionally, as  a  hard  skin  forms  on  the  alloy  with  age. 

Another  safeguard  against  low  water  is  the  alarm  whistle.  This 
is  attached  to  the  boiler  at  lowest  water  level.  If  the  water  is 
allowed  to  drop  below  that,  the  steam  rushes  into  the  whistle  and 
gives  the  alarm.  It  is  specially  to  be  commended  for  boilers  having 
little  water  space  or  depth  above  the  crown  sheet  of  the  furnace. 

Put  the  line  on  cylinder  exactly  on  a  level  with 
the  waterline  in  boiler  ;  screw  the  three-way  valve 
into  boiler  the  same  distance  below  waterline  in 
boiler  that  it  is  from  the  line  on  cylinder  to  center  of 
three-way  valve  when  screwed  in  its  place  to  bottom 
of  cylinder  ;  then  couple  cylinder  on  to  valve,  and 
connect  pipe  where  you  get  dry  steam  at  top.  Steam 
should  be  blown  through  the  three-way  valve  once  a 
week.  When  the  three-way  valve  is  screwed  out,  it 
allows  the  passage  of  water  from  boiler  through  up 
into  cylinder,  and  then  the  .  gauge  is  in  working 
order.  When  it  is  screwed  in,  it  allows  the  steam 
to  pass  down  through  the  cylinder,  while  at  the 
same  time  it  shuts  the  water  from  the  boiler. 
Place  the  cylinder  as  near  the  boiler  as  possible. 
THE  FEED  WATER  passes  into  the  boiler  through 
a  check  valve  in  which  the  valve  has  no  stem,  but 
constantly  drops  back  into  its  seat,  thereby  prevent- 
ing the  boiler  water  from  escaping  back  into  the  feed 
pipe.  Each  stroke  of  the  feed  pump  forces  the  valve  up,  so  that  the 
feed  is  delivered  intermittently.  Applying  the  ear  to  the  valve  will 
tell  whether  the  check  is  working  properly.  If  the  valve  becomes 
heated  it  is  a  sign  that  back  water  from  the  boiler  is  escaping.  A 


FIG.   26. 
LANE'S   Low 
WAT  ER    AND 
ALARM   GAUGE. 


Boiler  Mountings. 


59 


detached  stem  serves  in  larger  vessels  to  regulate  the  feed  by  screw- 
ing up  or  down,  varying  the  lift  of  the  loose  valve.  It  is  better, 
however,  to  regulate  the  feed  by  a  separate  valve,  allowing  the  check 
to  have  free  play  to  keep  it  clear.  An  escape  valve  is  sometimes 
fitted  to  the  feed  pipe  to  prevent  overloading  it,  risking  a  burst  in 
the  pipe. 


FIG.  27. — CHECK  VALVE.     JENKINS  BROS.,  NEW  YORK. 

Launches  and  small  yachts  are  now  commonly  supplied  with  an 
"  injector  "  instead  of  feed  pump.  There  are  numerous  devices  of 
the  kind  in  the  market,  the  original  invention  being  known  as  the 
Giffard.  The  injector  is  more  reliable  than  a  small  pump,  as  there 
are  no  valves  to  clog  and  fewer  parts.  It  occupies  less  space  and 
requires  less  attention.  The  steam  used  in  its  operation  is  con- 
densed in  the  feed  water,  heating  it  and  returning  it  to  the  boiler  in 
that  state  without  a  special  feed  heater.  The  working  of  an  injector 
can  be  explained  as  follows  :  Steam  from  the  boiler  enters  a  conical 
receiving  tube  at  the  head  of  the  instrument.  At  the  mouth  of  the 
cone  the  escape  of  the  steam  will  suck  the  air  from  a  branch  pipe 
leading  to  the  sea  through  the  boat's  bottom,  and  the  sea  water  or 


Boiler  Mountings. 


suction  will  be  drawn  up  the  branch  pipe  owing  to  the  partial  vacuum 
created.  The  suction  water  then  meets  the  steam  at  the  nozzle  of 
the  receiving  cone  in  the  instrument.  The  water  receives  the  impact 
of  the  steam,  condenses  it  and  acquires  considerable  velocity  as  a  jet, 
enough  to  force  its  way  through  a  delivering  tube,  past  a  check 
valve,  into  the  boiler  against  the  boiler  pressure.  The  power  of  the 
feed  to  enter  the  boiler  is  derived  from  its  weight  moving  at  the 
velocity  acquired  from  impact  with  the  steam  in  the  injector.  If  too 
much  water  be  admitted,  it  will  not  acquire  energy  enough,  and  if 


FIG.  28. 
HANCOCK  INSPIRATOR. 


FIG.  29. 
HANCOCK  LOCOMOTIVE  INSPIRATOR. 


too  little  in  proportion  to  the  steam  pressure,  the  energy  will  also 
be  diminished  for  lack  of  sufficient  weight,  as  energy  is  the  product 
of  weight  and  the  square  of  its  velocity.  Hence  an  injector  with 
fixed  parts  would  be  suitable  only  to  a  given  steam  pressure.  For 
different  pressures,  the  amount  of  water  admitted  would  need 
regulating  by  a  valve  or  automatic  piston  arrangement.  The  first 
would  need  constant  attention,  and  the  latter  is  liable  to  fail  in  its 
action.  To  overcome  these  drawbacks  of  the  ordinary  injector,  the 
Hancock  Inspirator  was  devised  and  is  now  in  general  use  in  launches 
and  yachts.  Fig.  28  shows  the  instrument  in  section,  and  Fig.  29  is 


Boiler  Mountings.  61 

an  elevation  of  the  locomotive  pattern  adapted  to  marine  use,  and 
operated  by  one  handle.  The  arrows  in  Fig.  28  make  the  action 
clear.  There  are  no  pistons  or  movable  parts.  An  ordinary  injector 
is  a  single  apparatus  requiring  adjustment  for  different  pressures, 
but  the  Hancock  injector  is  double,  one-half  being  a  "  lifter  "  and 
the  other  the  "  forcer,"  the  first  raising  and  the  latter  delivering  the 
feed  at  any  pressure.  It  will  lift  water  25  ft.  with  about  45  Ibs.  of 
steam,  and  will  take  it  140  deg.  Fahr.  on  a  lift  of  3  or  4  ft.  On  a 
lift  of  25  ft.  the  suction  should  not  be  over  100  deg.  The  tempera- 
ture of  the  delivery  will  be  increased  about  loodeg.  The  essential 
conditions  of  its  successful  operation  are  a  tight  suction  and  dry 
steam  direct  from  boiler,  not  from  another  pipe. 

The  suction  pipe  should  be  two  or  three  sizes  larger  than  the  con- 
nection for  a  high  lift  or  long  draft.  In  attaching,  be  careful  to 
blow  out  steam  pipes  before  connecting  to  clear  them  of  red  lead  or 
filings  which  would  stop  up  the  instrument.  The  suitable  size  is 
determined  by  the  capacity  of  the  boiler,  as  follows :  When  con- 
sumption of  fuel  is  known,  the  pounds  of  coal  consumed  per  hour 
will  be  the  number  of  gallons  evaporated  per  hour  and  to  be  sup- 
plied by  the  inspirator.  When  the  -grate  surface  is  known,  and  the 
draft  natural,  multiply  the  grate  in  sq.  ft.  by  9  for  the  gallons  evapo- 
rated per  hour.  For  forced  draft  allow  50  per  cent.  more.  Check 
valve  to  boiler  should  never  be  smaller  than  ^  in.,  the  usual  %  in. 
valve  being  worthless.  In  light  draft  yachts  subject  to  rolling  or 
pitching  in  a  sea,  the  suction  is  prevented  from  drawing  in  air  by 
the  addition  of  a  small  well  in  which  the  sea  pipe  rises  inside  of  an 
elbow  above  the  level  of  the  inspirator  suction,  thereby  keeping  the 
elbow  or  T  full  of  water  as  a  stop  to  the  suction,  allowing  air  taken 
in  to  escape  at  the  top  of  the  well.  To  start  the  inspirator  draw 
back  the  lever  sufficiently  to  open  the  overflow  valves  and  bring 
water,  and  then  draw  back  to  the  stop,  which  closes  the  overflow, 
and  diverts  the  jet  into  the  feed  pipe  leading  to  the  boiler. 

BLOW-OFF  VALVES  are  fitted  to  all  boilers,  one  near  the  level  at 
which  the  water  is  carried,  known  as  the  surface-blow,  and  the  other 
at  the  bottom,  known  as  the  bottom-blow.  As  the  boiler  water  is 
evaporated  into  steam,  the  remaining  water  becomes  denser,  for  the 


62  Boiler  Mountings. 

salt  of  sea  water  and  other  impurities  are  left  behind.  A  deposit, 
principally  sulphate  of  lime,  will  be  precipitated  upon  the  interior 
surface  of  the  boiler  shell  and  tubes,  forming  a  thin  sheet  of  scale 
which  is  a  very  poor  conductor  of  heat.  If  this  scale  accumulates 
and  hardens,  serious  damage  will  result  from  overheating  the  sur- 
faces exposed  to  the  fire,  or  "burning,"  as  the  cooling  boiler  water 
on  the  inside  does  not  come  in  contact  with  the  metal  for  its  pro- 
tection. 

To  prevent  such  results,  a  portion  of  the  boiler  water  is  period- 
ically "blown  off"  and  replaced  by  additional  feed  water,  so  that 
the  average  density  of  the  water  in  the  boiler  may  be  kept  below  the 
point  at  which  serious  deposit  takes  place.  The  water  blown  off  has 
already  been  heated  while  the  fresh  feed  is  taken  in  cold,  hence  a 
waste  of  heat  necessarily  accompanies  the  operation.  This  is  called 
the  "loss  by  blowing  off."  In  part  this  is  made  up  by  passing  the 
cold  feed  through  special  feed  water  heaters  deriving  their  heat 
from  the  exhaust  steam  of  non-condensing  engines.  In  condensing 
engines,  however,  the  only  source  of  heat  available  is  from  the  water 
blown  off.  This  is  led  through  a  series  of  pipes  surrounded  by  the 
cold  feed,  so  that  part  of  the  escaping  heat  is  transferred  to  the 
fresh  feed. 

The  higher  the  temperature  of  the  water,  the  greater  will  be  the 
precipitation,  hence  it  is  the  custom  to  provide  a  continual  surface 
discharge  termed  "surfacing"  or  "scumming."  The  density  least 
favorable  to  the  formation  of  scale  is  a  matter  of  judgment  and 
experiment.  The  common  rule  in  the  U.  S.  Navy  is  to  carry  the 
water  at  a  density  of  i^  by  the  salinometer,  and  most  engineers  fol- 
low this  direction.  Mr.  Geo.  W.  Baird,  U.  S.  N.,  has  found  a 
higher  density  preferable.  The  ground  taken  was  that  if  we  carry 
the  water  at  a  high  density,  we  do  not  have  to  blow  off  so  much  nor 
supply  so  much  sea-water  feed.  If  we  blow  less,  we  pass  less  sea- 
water  through  the  boiler  and  less  scale  is  accumulated.  The  solid 
matter  other  than  the  sulphate  of  lime  in  the  boiler  does  no  harm 
until  the  density  of  about  3^  is  reached,  which  will  be  the  limit 
beyond  which  we  cannot  go.  Experiments  were  carried  out  on  two 
naval  vessels  a  few  years  ago  to  test  Mr.  Baird's  proposition.  In 


Boiler  Mountings. 


one  boiler  the  water  was  kept  at  the  regulation  density  of  i^,  and 
in  the  other  at  2^,  accompanying  conditions  being  in  other  respects 
alike.  After  a  four  months'  cruise,  it  was  found  that  the  boiler 
carrying  water  at  the  low  density  of  i%  was  cleaned  of  scale  twice, 
and  that  the  boiler  carrying  the  water  at  the  higher  density  of  2% 
required  no  "scaling"  at  all,  and  at  the  end  of  the  cruise  was  freer 
from  scale  than  the  other. 


FIG.  30. — SALINOMETER. 


FIG. 


31. — LONG'S  SALINOMETER. 
STEAM  GAUGE  Co. 


AMERICAN 


THE    SALIXOMETER  consists  of  a  glass  tube    with  ballast    in    a 
bulb  at  the  lower  extremity.     When   dropped   into   fresh  water  the 


64  Boiler  Mountings. 

line  of  flotation  supplies  the  o  of  the  scale.  If  placed  in  water  con- 
taining i  Ib.  of  saline  matter  in  32  Ibs.  of  water,  it  will  rise  to  ^h  of 
the  scale;  when  in  water  containing  2  Ibs.  of  saline  matter  in  32  Ibs. 
of  water,  it  rises  to  the  -fa  mark  on  the  scale,  and  so  on.  If  the 
water  in  a  boiler  is  said  to  have  a  density  of  i^,  it  means  that  the 
salinometer  would  float  half  way  between  -h  and  -&  of  the  scale. 
A  density  of  2^  means  that  the  instrument  will  float  one-quarter 
the  distance  between  •&  and  *&.  The  scale  steadily  contracts  down 
the  instrument,  because  at  greater  densities  the  displacement  of  the 
instrument  becomes  less  and  less,  while  its  own  weight  remains  con- 
stant. The  salinometer  is  graduated  for  a  temperature  of  200  deg. 
Fahr.  and  will  not  serve  for  other  temperatures,  as  the  density  varies 
with  the  latter.  A  difference  of  lodeg.  in  the  water  will  cause  a 
difference  of  ^  in  the  scale.  To  facilitate  the  use  of  the  instrument 
in  practice,  the  boiler  water,  after  being  drawn  off,  must  be  cooled 
down  to  200  deg.  by  some  method  which  will  allow  continuous  obser- 
vation. This  is  accomplished  by  passing  the  boiler  water  through  a 
coil  surrounded  by  cold  water  according  to  the  plan  of  Chief  Engi- 
neer Fithian,  U.  S  N.,  or  by  having  a  separate  cylindrical  casing  to 
receive  the  hot  water  and  steam  from  the  boiler,  the  water  flowing 
over  into  the  tube  in  which  the  salinometer  floats,  while  the  steam 
escapes  without  reaching  the  observer.  The  salinometer  tube  is 
surrounded  by  cold  water  in  an  outer  tube.  By  regulating  the  sup- 
ply of  boiler  and  cooling  water,  an  even  temperature  of  200  deg.  can 
be  maintained.  This  is  the  plan  devised  by  Sewell  and  Long  of  the 
U.  S.  Navy. 

Such  instruments  are  supplied  only  to  sea-going  yachts.  In 
launches  and  steamers  which  make  a  harbor  frequently,  the  sali- 
nometer is  seldom  brought  into  use.  The  boiler  water  is  entirely 
changed  after  every  run  and  the  engineer  blows  off  occasionally 
according  to  his  judgment.  In  condensing  engines  the  frequent 
renewal  of  all  the  boiler  water  is  an  advantage,  as  it  gets  rid  of  dele- 
terious matters  from  the  condenser  which  the  salinometer  would  not 
detect.  By  filling  up  with  fresh  water  before  starting,  a  day's  run 
can  be  made  before  the  water  will  reach  a  density  of  3,  even  if  the 
feed  be  sea-water. 


Boiler  Mountings.  65 

FEED  PUMPS  of  the  direct-acting  variety  with  boiler  connections 
supply  feed  water  when  an  injector  is  not  used,  and  are  always  a  part 
of  sea-going  machinery.  They  work  independently  of  the  engine, 
although  in  launches  frequently  from  an  eccentric  on  the  shaft  or 
from  the  piston  crosshead.  The  independent  pump  can  be  run 
after  the  yacht  has  come  to  an  anchor  or  is  in  dock,  so  that  the 
steam  can  be  run  down  and  the  boiler  filled  ready  for  firing  again. 


FIG.    32.— WORTHINGTON  BOILER  FEED   PUMP. 

The  Worthington  Feed  Pump,  like  all  others  made  by  the  Henry 
R.  Worthington  Hydraulic  Works  of  Brooklyn,  N.  Y.,  are  of  the 
"duplex  pattern."  There  are  two  steam  and  two  water  pistons,  as 
the  perspective  illustration  will  show.  Such  arrangement  insures 
smoothness  of  working,  efficiency  and  reliability.  The  valves  of  the 
steam  cylinders  are  ordinary  slides,  the  simplest  and  most  reliable  of 
all  kinds.  They  receive  motion  from  a  vibrating  arm  which  swings 
through  the  whole  length  of  the  stroke  free  from  sudden  blow.  The 
work  of  the  pump  being  divided  between  two  engines,  the  wear  is 
also  divided  and  the  lifetime  increased.  The  discharge  is  also  con- 
tinuous and  steady. 


FIG.  33. 


NOMENCLATURE   OF    THE  WORTHINGTON    FEED   PUMP. 


i.  Steam    cylinder 

21.  Piston  rod  stuffing 

(No.  i   or   No.  2 

box  gland. 

side). 

22.  Steam  cylinder  foot 

2.  Steam    cylinder 

24.  Piston  rod. 

head.      ' 

25.  Valve  rod  head  pin. 

3.  Slide  valve. 

26.   Long  valve  rod  link 

4.  Valve  rod  nut. 

27.  Short   valve   rod 

5.  Valve  rod. 

link. 

6.  Valve  rod  gland. 
7.  Valve  rod  head. 

28.  Long  lever. 
29.  Rock  shaft  key. 

8.  Steam  chest. 

30.  Upper  rock  shaft. 

9.  Steam  chest  cover. 

31.  Lower  rock  shaft. 

lo.  Steam  pipe. 

32.  Short  lever. 

ii.  Lubricator. 

33.  Crank  pin. 

2.  Piston  ring. 
3.  Piston  follower. 

34.  Crosshead. 
35.  Crosshead  position 

5.  Piston  body. 
6    Piston  spring. 

pin. 
36.  Crosshead  key. 

7.  Piston  tongue. 

37.  Crosshead  pin. 

8.  Piston  tongue 

38.  Crosshead  link. 

spring. 

39.  I  /ever  pin. 

19.  Piston  nut. 

41.  Cross-stand. 

20.  Piston  rod  stuffing 

42.  Waste  cock. 

box. 

43.  Pet  cock. 

44.  Water  cylinder. 

45.  Water   cylinder 

head. 

46.  Thumb  plugs. 

52.  Water  piston  nut. 

53.  Water   piston  jam 

54.  Plunger  rod  stuff- 

ing box. 

55.  Plunger  rod   stuff- 

ing box  gland. 

56.  Force  chamber. 

57.  Valve  guard. 

58.  Valve  spring. 

59.  Valve. 

60.  Valve  seat. 
67.  Air  chamber. 

80.  Stuffing     box    fol- 

lower. 

81.  Sectional     stuffing 

box  follower. 

82.  *  Side  -  feed    cross- 

head. 

83.  Side-feed  plunger. 


84.  Side-feed     stuffing 

box  gland. 

85.  Side-feed      pump 

barrel. 

86.  End-feed     pump 

barrel. 

87.  End-feed    pluncer. 

88.  End-feed     stuffing 

box  gland. 

89.  End-feed     stuffing 

box  follower. 

90.  End-feed  air  cock. 

91.  Solid  water  piston. 

92.  Packed  water  pis- 

ton body. 

93.  Packed  water  pis- 

ton follower. 

94.  Packed  water  pis- 

ton packing. 

95.  Packed  water  pis- 

ton    setting -out 
ring. 

96.  Water  end  foot. 


*  Side-feeds  were  attached  to  pumps  built  prior  to  1885.     The  End-feed  is  now  standard. 

[66] 


Boiler  Mountings. 


The  capacity  of  the  pump  is  shown  in  the  following  table  of  sizes, 
the  number  of  strokes  per  minute  being  from  75  to  150. 


Diameter 
of  Steam 
Cylinders. 

Diameter 
of  Water 
Plungers. 

Length 
of 
Stroke. 

Gallons  delivered  per  min- 
ute by   BOTH    plungers  at 
stated  number  of  strokes. 

Diameter  of  plunger 
required  in  any  sin- 
gle cylinder  pump  to 
do  the  same  work  at 

same  speed. 

3 

2 

3 

6  to  16 

2^  ins. 

4^ 

2^ 

4 

15  to  30 

4       ins. 

5^ 

3^ 

5 

30  to  60 

5      ms. 

6 

•        4 

6 

50  to  80 

5^  ins. 

In  small  sizes  for  steam  launches,  Chas.  P.  Willard  &  Co.,  of 
Chicago,  use  a  single  cylinder  pump  correponding  to  the  following 
dimensions  : 


Size  Steam 
Cylinder. 

Size  Water 
Cylinder. 

Length  of 
Stroke. 

Capacity 
Per  Minute. 

2^  inches. 
3       inches. 
3j£  inches. 

1^   inches, 
i^  inches. 
2^"   inches. 

3  inches. 
3  inches. 
3   inches. 

3^  galls. 
4K  galls. 
72^  galls. 

FIG.  34. — FEED  PUMP  FOR  LAUNCHES. 


The  pump  is  driven  up  to  about  150  strokes  per  minute.  Inject- 
ors should  always  be  added,  so  that  if  the  pump  gives  out,  there 
will  be  no  danger  of  low  water  in  the  boiler.  Independent  steam 
pumps  are  more  economical  than  injectors. 


68  Boiler  Mountings. 

Long  straight  steam  pipes  should  be  avoided,  as  they  will  break 
in  consequence  of  expansion,  especially  where  high  steam  is  used. 
Elbows  should  be  introduced  to  give  the  needed  play  or  else  special 


THE  GORDON   *   MAXWELL  CO. 

FIG.  35. — FEED  PUMP  WITH  PLUNGER. 

"expansion  joints"  must  be  fitted.  The  working  parts  of  such  joints 
should  be  of  brass  or  lined  with  the  same  to  prevent  rust  and  friction. 
The  pipe  is  held  in  place  by  bolts  from  stuffing  box  to  lugs  or  flange 
on  the  pipe  to  prevent  their  being  blown  out  upon  admission  of 
steam.  The  nuts  of  these  bolts  should  allow  enough  play  to  the 
working  parts. 


IV. 
THE    ENGINE    AND    ITS    PARTS. 

THE  piston  of  an  engine  receives  its  reciprocal  motion  by  alter- 
nately admitting  steam  to  the  top  and  bottom,  and  permitting 
escape  to  the  steam  which  has  done  its  work  on  the  opposite  end  of 
the  piston  to  that  which  is  receiving  steam.  Fig.  36  is  a  section  of  a 
cylinder  in  which  the  piston  has  arrived  at  the  end  of  the  upward 
stroke,  steam  being  cut  off  by  a  single  ported  slide  valve. 

Steam  from  the  boiler  is  admitted  by  the  stop  valve  or  throttle  to 
the  valve  chest  as  a  receiver  This  brings  about  a  pressure  in  the 
valve  chest  equal  to  that  in  the  boiler  and  presses  the  valve  firmly  to 
its  seat.  The  faces  of  seat  and  valve  must  be  accurately  planed  and 
lubricated  to  allow  free  travel.  In  Fig.  37,  the  valve  just  covers 
both  steam  ports  and  the  engine  would  be  at  rest. 

A  valve  complying  with  this  condition  is  said  to  have  no  "lap," 
meaning  that  it  does  not  overlap  the  ports  at  its  ends.  Such  a  valve 
will  have  to  travel  twice  the  width  of  a  port  to  accomplish  its 
objects.  The  distance  traveled  is  equal  to  the  " throw"  of  the 
eccentric  on  the  crank  shaft  from  wrhich  the  valve  receives  its  motion. 
The  "throw"  is  twice  the  distance  between  the  center  of  the  shaft 
and  the  center  of  the  eccentric  disc,  the  latter  being  really  a  substi- 
tute for  a  regular  crank. 

If  the  valve  in  Fig.  37  be  moved  down  to  the  position  in  Fig.  38, 
steam  will  have  been  admitted  to  the  upper  port  a  and  the  piston  P 
will  have  been  forced  downward.  At  the  same  time,  the  steam  left 
below  the  piston  from  the  previous  stroke  will  escape  through  port  b 


;o 


The  Engine  and  Its  Parts. 


into  the  exhaust  passage  c  connecting  with  the  condenser,  or  the 
smoke  stack,  if  the  engine  be  non-condensing.  In  Fig.  38,  before 
the  piston  has  reached  the  end  of  the  down  stroke,  the  valve  will 


FIG.  36. — SECTION  OF  CYLINDER  AND  VALVE  CHEST. 


A.  Cylinder. 

B.  Piston. 

C.  Piston  rod. 

D.  Valve  chest. 

E.  Exhaust  port. 

F.  Steam  ports. 

G.  Slide  valve. 


H.     Valve  stem. 

I.     Glands. 

J.     Guide  to  relieve  valve  of  pressure. 

K.     Ribs  on  steam  chest  cover. 

S.     Position  of  steam  pipes. 

X.     Position  of  exhaust  pipe. 


have  changed  its  motion  and  proceed  upward,  opening  the  port  b  to 
the  steam  and  connecting  the  upper  port  a  with  the  exhaust  pas- 
sage c,  as  in  Fig.  39. 


The  Engine  and  Its  Parts. 


A  consideration  of  these  diagrams  will  show  that  steam  must  "fol- 
low full  stroke,"  and  that  no  work  by  expansion  can  be  done.  For, 
if  we  were  to  set  the  eccentric  in  such  a  way  as  to  cut  off  the  steam 
from  the  upper  port  before  the  piston  has  reached  the  end  of  the 
down  stroke,  the  exhaust  port  would  likewise  be  closed  and  the  lower 
end  of  the  cylinder  left  full  of  steam.  The  piston  would  continue 
to  descend  until  the  back  pressure  on  the  under  side  equaled  the 
pressure  of  the  expanded  steam  on  the  upper  side  ^f  the  piston,  the 


FIG.  37. 


FIG.  38.  FIG.  39. 

VALVE  MOTION. 


FIG.  40. 


engine  coming  to  a  standstill.  To  work  expansively,  this  simplest 
form  of  the  slide  valve  must  be  modified  by  the  addition  of  "lap," 
that  is  the  extension  of  the  valve  at  its  external  extremities,  so  that 
the  steam  port  may  be  closed  before  the  exhaust.  But  this  carries 
with  it  an  error  in  the  opposite  respect. 

In  Fig.  40,  the  lap  added  is  shown  by  the  extension  a  and  b. 
Now  while  a  will  close  the  upper  steam  port  before  the  piston  has 
completely  descended,  the  corresponding  lap  b  at  lower  end  of  valve 
will  fail  to  open  the  lower  steam  port  in  time  for  the  return  stroke. 


72  The  Engine  and  Its  Parts. 

We  must  therefore  "set  the  eccentric  ahead."  That  is,  the  valve 
should  be  given  such  motion  relative  to  the  piston,  that  it  will  have 
traveled  far  enough  on  its  upward  stroke  to  open  port  b  when  the 
piston  is  ready  to  ascend.  The  stroke  of  the  valve  relative  to  that 
of  the  piston  is  under  our  control,  for  the  eccentric  disc  on  the 
engine  shaft,  from  which  the  valve  receives  motion,  can  be  shifted 
around  the  shaft,  or  "set  ahead"  as  we  desire.  This  will  alter  the 
stroke  of  the  valve  in  comparison  with  that  of  the  piston.  The  arc 
through  which  the  eccentric  is  set  ahead  to  meet  the  addition  of  lap 
is  called  the  "angular  advance."  By  putting  the  valve  ahead  to 
adjust  the  opening  of  the  steam  ports,  we  will  introduce  a  new  error 
on  the  interior  of  the  valve.  From  Fig.  40,  it  can  be  seen  that  if  the 


FIG.  41. — ECCENTRIC  Disc. 


A.  Center  of  engine  shaft. 

B.  Center  of  eccentric  when  up. 

C.  Center  of  eccentric  when  down. 
B.  C.     Throw  of  eccentric. 


m.  n.  Angular  advance  of  eccentric  beyond 
right  angle  with  crank  to  meet  the 
"lap'  of  a  valve. 


valve  be  set  ahead  enough  to  open  steam  port  <£,  the  exhaust  on  top 
will  open  too  soon  by  that  amount  before  the  piston  has  descended, 
and  no  work  could  be  done  by  expansion  on  the  upper  side  of  the 
piston,  as  the  steam  would  escape  through  the  exhaust.  To  keep 
the  latter  port  closed  until  the  end  of  the  downward  stroke,  we  must 
add  lap  d  on  the  inside  of  the  valve,  and  the  same  amount  at  e  for  the 
return  stroke.  If  the  same  amount  of  lap  be  added  on  the  exhaust 
side  of  the  valve  as  on  the  steam  side,  it  would  close  the  exhaust  at 
the  time  steam  is  cut  off,  which  would  be  too  soon  and  cause  too 
great  back  pressure  or  "cushioning."  For  this  reason  the  lap  on 
interior  of  valve  must  be  less  than  that  added  to  exterior.  The 
eccentric  is  also  set  ahead  a  little  more  than  necessary  to  open  the 


The  Engine  and  Its  Parts.  73 

steam  port  a  little  before  the  extreme  end  of  stroke,  so  that  the 
piston  may  be  brought  gradually  to  a  point  of  rest  before  altering  its 
motion,  by  the  cushioning  of  the  steam.  The  valve  is  then  said  to 
have  "lead."  Where  the  clearance  spaces  are  large,  closing  the 
exhaust  in  advance  will  supply  the  required  cushioning,  which  should 
be  equal  to  the  terminal  pressure  upon  the  piston.  In  such  cases 
"  lead  "  is  not  necessary. 

To  REVERSE  an  engine,  it  is  necessary  to  arrest  the  valve  and 
change  the  direction  of  its  travel,  thereby  reversing  the  admission 
and  escape  of  the  steam  on  the  head  of  the  piston.  For  example, 
the  steam  is  entering  on  top  and  the  exhaust  escaping  through 
the  lower  port.  If  we  suddenly  shift  the  valve,  so  as  to  close 
the  steam  port  above  and  place  that  part  of  the  cylinder  in  connec- 
tion with  the  exhaust  and  at  the  same  time  close  the  exhaust  below 
and  open  the  steam  port  instead,  the  piston  will  come  to  a  stop  and 
will  ascend  instead  of  completing  the  downward  stroke.  This  will 
cause  the  crank  to  turn  in  the  opposite  way  and  the  screw  shaft 
with  it. 

To  SHIFT  THE  VALVE  and  reverse  its  stroke,  a  second  eccentric 
is  required.  By  throwing  the  ahead-eccentric  out  of  action  and  the 
backing-eccentric  into  action,  the  result  is  accomplished.  This  is 
done  by  the  intervention  of  the  eccentric  gear.  In  Fig.  42,  the 
various  parts  of  a  small  launch  engine  are  explained  by  the  lettering 
attached.  The  engine  is  going  ahead,  the  ahead-eccentric  giving 
motion  to  the  valve  through  the  rod  E,  link  block  B  in  the  link  L, 
and  the  valve  stem  V.  To  reverse,  the  handle  H  of  the  lever  is 
moved  to  the  left  to  H1  .  This  will  draw  the  link  L  to  the  left  in 
the  dotted  position,  and  bring  ahead-eccentric  E  to  E1  and  the  back- 
eccentric  F  into  the  position  of  E  in  the  illustration,  at  the  same 
time  drawing  down  the  block  B  and  shifting  the  valve  to  suit.  This 
block  B  is  attached  to  the  valve  stem  by  a  pin,  but  the  link  slides 
back  and  forth  on  the  block.  Now,  when  rod  F  comes  into  line 
with  the  valve  stem  V,  the  latter  will  be  actuated  by  the  back-eccen- 
tric. This  is  keyed  to  the  shaft  in  a  position  so  related  to  that  of  the 
ahead-eccentric,  that  upon  being  thrown  into  gear  the  valve  will 
travel  in  opposite  direction.  If  the  link  be  thrown  over  half  way,  or 


K 


FIG,  42, — REVERSING  LAUNCH  ENGINE. 


A.  Cylinder  of  inverted  direct  acting  launch 

engine. 

K.  Cast  iron  standard  cr  frame. 

T.  Bed  plate  screwed  down  to  keelsons. 

U.  Engine  keelsons  in  bottom  of  boat. 

C.  Valve  chest,  steam  pipe  not  seen. 

X.  Exhaust  from  valve  chest. 

Z.  Guides  for  piston  crosshead. 

N.  Connecting  rod  from  crosshead  to  crank. 

V.  Valve  stem,  connected  by  pin  with  blo^k  B.  : 

B.  Link  block,  having  free  travel  in  link. 

L.  Link  for  throwing  eccentrics  in  or  out  of  | 
gear. 


R.    Connecting  arm  between  link  and  reversing 

lever. 
H.     Reversing  lever  with  notched  quadrant  and 

latch. 

E.  Ahead-eccentric  rod  in  action. 

F.  Back-eccentric  rod  out  of  action. 

S.     Eccentric    straps    in    which    the    eccentric 

revolves. 
M.     Eccentric  disc  keyed  to  crank  shaft. 

G.  Clutch  coupling  to  line  or  screw  shaft. 

P.     Feed  pump  worked  by  eccentric  on  shaft. 

[74] 


The  Engine  and  Its  Parts.  75 

in  "mid-gear,"  the  valve  will  cover  both  steam  ports,  and  the  engine 
comes  to  a  stop. 

If  thrown  over  between  mid-gear  and  full-gear  ahead  or  astern, 
the  travel  of  the  valve  will  be  shortened  proportionally,  opening  and 
closing  the  ports  sooner,  admitting  less  steam  than  when  in  full-gear. 
The  effect  is  the  same  as  diminishing  the  throw  of  the  eccentrics. 
Of  course  the  saving  in  steam  would  be  accompanied  with  a  loss  in 
power,  as  the  mean  pressure  would  decrease.  The  engine  would 
therefore  be  going  at  reduced  speed. 

In  practice  the  valve  is  so  adjusted  as  to  admit  steam  from  half  to 
two-thirds  the  stroke,  which  is  all  that  can  be  done  under  the  circum- 
stances. Where  greater  expansion  is  required,  it  is  necessary  to 
resort  to  a  third  eccentric,  giving  motion  to  a  separate  or  "  expansion 
valve  "  seated  on  back  of  the  slide  valve,  cutting  off  the  steam  from 
ports  in  the  slide  valve  at  any  desired  fraction  of  the  stroke.  When 
the  fraction  can  be  altered  at  option,  the  expansion  valve  is  known 
as  a  "variable  cut-off."  Such  alteration  is  often  effected  by  right 
and  left  screw  threads  on  the  expansion  valve  stem,  enabling  two 
separate  valves  to  be  drawn  closer  or  spread  apart  by  turning  the 
screws,  in  that  way  changing  the  travel  of  the  expansion  valve  above 
the  slide  valve. 

For  high  pressures,  "piston  valves"  such  as  shown  in  the  Wells 
Balance  Engine,  take  the  place  of  the  slide  valve,  as  they  are 
"balanced"  by  the  steam  in  the  chest  surrounding  them,  thereby 
preventing  cutting  the  valve  seat. 

THE  INDICATOR  is  an  invaluable  instrument,  by  means  of  which 
we  obtain  a  graphic  delineation  of  the  internal  working  of  the  cylinder. 
The  first  apparatus  of  the  kind  was  invented  by  James  Watt.  From 
the  "  diagram "  taken  while  the  engine  is  at  work  we  are  able  to 
deduce:  The  initial  pressure  on  the  piston;  the  pressure  at  all  por 
tions  of  the  stroke,  during  which  we  follow  up  with  steam;  the  exact 
point  of  cut-off;  the  reduction  of  pressure  due  to  expansion  during 
remainder  of  stroke  terminal  pressure;  counter-pressure  in  non 
condensing  engines;  vacuum  of  condensing  engines;  cushioning;  lead 
and  mean  effective  pressure  for  entire  stroke.  In  connection  with  the 
mean  pressure,  stroke  and  number  of  revolutions,  we  are  enabled  to  as- 


The  Engine  and  Its  Parts. 


certain  the  power  developed.  The  mean  power,  compared  with  the 
steam  supplied  from  the  boiler,  gives  us  the  cost  of  power  in  steam,  and 
if  referred  to  the  coal  consumption,  of  power  in  fuel.  The  diagram  en- 
ables us  also  to  determine  whether  the  valves  are  set  and  work  properly ; 
whether  steam  and  exhaust  passages  are  of  right  size;  whether  there 
is  any  leakage;  the  loss  between  boiler  and  engine  pressure;  efficiency 
of  jacketing,  and  of  expansion  in  one  or  more  cylinders;  to  apportion 
the  work  done  in  the  cylinders  of  compound  engines,  etc.  The  in- 


FIG.  43-  FlG-  44. 

THOMPSON  IMPROVED  INDICATOR. 

dicator  is,  in  fact,  the  stethoscope  of  the  engineer.  Without  it  we 
would  be  working  in  the  dark,  and  our  stock  of  information  would  be 
limited  and  untrustworthy.  No  intelligent  reading  of  the  economics 
of  the  engine  would  be  within  our  control. 

The  operation  of  the  indicator  can  be  described  with  the  aid  of 
Figs.  43  and  44,  which  are  outside  and  inside  illustrations  of  the 
Thompson  Improved  Indicator,  manufactured  by  the  American  Steam 
Gauge  Co.,  of  Boston.  It  consists  essentially  of  a  small  cylinder  and 
large  drum  rotating  on  a  spindle  in  a  connecting  arm.  Steam  from 


The  Engine  and  Its  Parts.  77 

the  engine  is  admitted  into  the  lower  end  of  the  small  cylinder,  and 
presses  upon  a  piston  with  a  resisting  spring  above  it.  As  the  piston 
is  forced  upward,  a  rod  -is  driven  out  of  the  top  of  the  cylinder.  To 
the  head  of  this  rod  is  attached  a  lever  containing  a  pencil  at  its 
extremity.  The  pencil  point  presses  against  the  large  or  "card 
cylinder  "  of  the  instrument.  This  is  caused  to  rotate  back  and  forth, 
a  part  of  a  revolution  in  one  direction,  by  means  of  a  cord  attached 
to  a  suitable  part  of  the  engine,  and  the  return  in  opposite  direction 
by  means  of  a  spring  in  the  base  of  the  card  cylinder.  A  piece  of 
paper  is  wrapped  around  the  card  drum  and  held  in  place  by  vertical 
fingers  screwed  to  the  base. 

If  steam  is  admitted  under  the  piston  of  the  instrument,  the  pencil 
will  ascend,  marking  a  vertical  line  on  the  paper  cylinder,  if  the  latter 
is  not  caused  to  rotate.  If  the  pencil  remains  fixed,  while  the  paper 
cylinder  is  rotated,  the  line  marked  by  the  pencil  will  be  a  horizontal. 
If  the  pencil  ascends  or  descends,  and  the  paper  cylinder  is  rotated 
at  the  same  time,  the  line  drawn  by  the  pencil  point  will  be  a  curve, 
the  shape  of  which  depends  upon  the  relative  amount  of  vertical 
motion  of  pencil  and  rotative  motion  of  the  paper  cylinder. 

Supposing  the  instrument  attached  and  in  working  order,  the  con- 
sideration of  an  actual  diagram  will  further  a  clearer  understanding. 
Fig.  45  is  the  sheet  of  paper  removed  from  the  paper  cylinder  and 
flattened  out.  The  o  line,  or  "atmospheric  line,"  is  obtained  by 
causing  the  cylinder  to  rotate  before  the  admission  of  steam,  the 
atmosphere  pressing  alike  on  top  and  bottom  of  the  piston.  If  dur- 
ing the  operation  the  pencil  is  forced  above  that  line,  it  will  show  a 
pressure  greater  than  that  of  the  atmosphere.  If  the  pencil  descends 
below  the  o  line,  it  is  due  to  a  pressure  less  than  that  of  the  atmos- 
phere on  the  piston  of  the  instrument.  Steam  being  admitted  into 
the  engine  cylinder  and  at  the  same  time  from  it  into  the  instrument, 
the  piston  of  the  latter  will  commence  to  rise,  describing  on  the 
paper  cylinder  a  vertical  line  from  a  up  to  b.  At  b,  the  paper  cylin- 
der, having  rotary  motion  coincident  with  the  travel  of  the  engine 
piston,  starts  to  revolve,  and  the  pencil  describes  the  line  b  to  c.  At 
c,  the  valve  in  the  valve  chest  of  the  engine  closes,  the  rest  of  the 
stroke  being  effected  by  expansion.  The  pressure  in  the  cylinder 


78  The  Engine  and  Its  Parts. 

gradually  falls  and  the  pencil  descends  while  the  paper  cylinder  con- 
tinues to  rotate.  These  two  motions  combined  produce  the  curve 
c  d.  At  d,  the  exhaust  port  opens  and  the  pencil  quickly  drops  to  e 
in  consequence  of  the  withdrawal  of  pressure.  The  engine  piston 
now  starts  on  the  return  stroke  and  the  spring  in  the  paper  cylinder 
causes  the  latter  to  reverse  its  rotation,  the  pencil  describing  the  line 
b  a  back  to  the  beginning  of  the  diagram. 

2  tn> 


FIG.  45. — INDICATOR  DIAGRAM. 

The  line  from  a  to  b  is  manifestly  the  "receiving  line,"  represent- 
ing the  rise  in  pressure  from  the  partial  vacuum  of  the  condenser  or 
exhaust  side  of  the  piston  up  to  the  time  the  piston  begins  to  move 
in  answer  to  the  admission  of  live  steam.  From  b  to  c  is  known  as 
the  "steam  line."  Its  length  represents  the  time  of  following  full 
steam.  It  does  not  rise  or  fall  because  the  pressure  remains  con- 
stant in  the  engine  cylinder  and  therefore  also  under  the  piston  of 


The  Engine  and  Its  Parts.  79 

the  instrument.  From  c  to  d,  the  pencil  drops  as  the  pressure  in  the 
cylinder  decreases  with  expansion.  It  is  called  the  expansion  line." 
Nearly  at  the  end  of  the  stroke,  upon  opening  the  exhaust  port,  the 
pressure  suddenly  drops  from  the  terminal  pressure  on  the  piston  at 
d  to  that  in  the  condenser  at  e.  This  is  called  the  "exhaust  line." 

The  return  stroke  of  the  engine  piston  moving  against  the  pres- 
sure in  the  condenser,  is  shown  from  e  to  a  and  is  horizontal,  because 
the  pressure  on  the  exhaust  side  of  the  engine  piston,  with  which 
side  the  instrument  is  in  communication,  is  constant.  This  is  called 
the  "back  pressure  line,"  or  incorrectly  the  "vacuum  line."  In  non- 
condensing  engines,  it  will  be  coincident  with,  or  but  little  above  the 
atmospheric  line  as  they  exhaust  into  the  smokestack  against  the 
pressure  of  the  atmosphere  and  any  back  pressure  from  the  escape 
pipe. 

The  numbers  on  right  side  of  diagram  are  a  scale  of  pressures  in 
Ibs.  The  numbers  along  the  top  represent  the  length  of  the  stroke 
in  feet.  It  will  be  seen  that  the  initial  piston  pressure  was  20  Ibs. 
and  the  vacuum  on  exhaust  side  of  piston  n,  equal  to  a  total 
unbalanced  pressure  of  31  Ibs.  per  sq.  in.  of  piston  area  at  beginning 
of  stroke.  The  cut-off  is  a  little  more  than  half  the  stroke.  The 
rounding  at  d  is  the  "lead  "  on  the  exhaust ;  the  exhaust  port  having 
opened  a  little  before  the  piston  arrived  at  the  end  of  its  stroke. 
The  round  at  a  represents  the  amount  of  cushioning  due  to  closing  of 
exhaust  port  before  end  of  stroke.  Without  lead  the  corners  would 
have  been  angular.  The  round  at  e  at  commencement  of  return 
stroke  is  the  back  pressure  still  in  cylinder.  The  scale  of  pounds 
pressure  will  depend  upon  the  strength  of  the  resisting  spring,  which 
is  made  to  allow  the  piston  of  the  instrument  a  certain  travel  for 
every  pound  of  pressure  put  upon  it.  The  scale  of  the  stroke  de- 
pends upon  the  extent  to  which  the  paper  cylinder  revolves  per 
stroke  of  engine  piston.  The  "mean  pressure  "  for  the  entire  stroke 
is  found  by  measuring  across  the  diagram  at  intervals  and  dividing 
by  the  number  of  intervals. 

THE  HORSE  POWER  is  obtained  by  multiplying  the  mean  unbal- 
anced pressure  per  square  inch  upon  the  piston  by  the  area  of  the 
piston  in  square  inches  and  again  by  the  speed  of  the  piston  in  feet 


8o  The  Engine  and  Its  Parts. 

per  minute  and  dividing  this  product  by  33,000.      If  A  =  area  of 
piston  in  inches,/  =  mean  pressure,  v  =  velocity  of  piston,  then  the 


I.  H.  P. 


33,000 

The  divisor  is  supposed  to  be  the  weight  which  a  stout  draft  horse 
can  raise  one  foot  high  in  one  minute  of  time,  hence  the  term  horse 
power  as  applied  to  the  work  of  an  engine.  The  speed  of  the  piston 
per  minute  is  equal  to  the  stroke  in  feet  multiplied  by  the  number  of 
strokes  per  minute. 

A  PERFECT  DIAGRAM  should  follow  Marriotte's  law  previously 
explained,  which  serves  as  the  standard  of  comparison.  It  can  be 
drawn  in  according  to  the  directions  given  for  apportioning  the 
lengths  of  the  ordinates  of  the  hyperbolic  curve  in  inverse  ratio  to 
the  volume  occupied  by  the  steam. 

Had  the  diagram  Fig.  45  shown  the  corner  cut  off  like  the  dotted 
line  s  /,  it  would  mean  that  the  exhaust  closed  too  soon,  occasioning 
excessive  cushioning  and  lowering  the  mean  unbalanced  pressure. 
Had  the  upper  corner  been  cut  off,  as  at  w  y,  the  steam  valve  would 
open  too  late.  Had  the  steam  line  dropped  to  m  n  instead  of  being 
nearly  horizontal,  it  would  indicate  cramped  passages  and  port  or 
the  throttle  not  opened  wide  enough,  for  the  pressure  in  cylinder 
would  not  have  been  maintained  as  it  ought  to  have  been  while  fol- 
lowing up.  Had  the  exhaust  corner  o  p  been  cut  off,  the  exhaust 
.  port  would  have  opened  too  soon.  Had  the  corner  g  r  been  cut  off, 
the  exhaust  port  wDuld  have  opened  too  late.  If  the  lead  to  the 
steam  side  were  excessive,  it  would  show  in  a  line  like  v  m. 

The  Thompson  Improved  Indicator  is  adapted  to  extreme  high 
pressures.  The  usual  piston  has  an  area  of  y%  sq.  in.,  which  with 
a  100  Ib.  spring,  provides  for  indicating  pressures  up  to  250  Ibs.  By 
substituting  a  smaller  piston  the  capacity  of  the  spring  can  be 
increased  to  500  Ibs.  Much  depends  upon  the  free  working  of  the 
instrument.  It  stands  to  reason  that  if  the  moving  parts  are 
hindered  in  their  play,  or  if  the  springs  are  not  true  in  their  action, 
the  results  will  be  deceptive. 

Before  applying  the  indicator,  it  should  be  taken  apart  and  care- 
fully cleaned  and  oiled.  Each  piece  should  be  proved  separately. 


The  Engine  and  Its  Parts.  81 

Put  them  together  without  the  piston  spring  and  lift  the  pencil  to 
see  if  it  will  fall  clear.  Then  put  in  the  spring  and  connect.  Give 
it  steam  to  warm  and  expand  all  parts.  Lead  should  not  be  used  in 
making  tight  connection,  as  it  is  liable  to  get  into  the  casings.  A 
suitable  coupling  comes  with  the  instrument.  The  lighter  the  spring 
used  the  higher  will  the  diagram  be  and  more  accurate  measure- 
ments can  be  taken,  as  the  scale  of  pressure  will  be  larger.  The 
diagram  should  have  a  height  of  say  two  inches.  The  following 
rule  will  give  the  maximum  pressure  to  which  each  spring  should  be 
subjected.  Multiply  the  number  or  scale  of  spring  by  2^,  and 
deduct  15  for  the  vacuum  allowance.  Example:  40  Ibs.  spring 
X  2}^  =  100 — 15  =  85  Ibs.,  the  maximum  pressure  for  the  40  Ibs. 
spring.  For  smaller  pressures  the  spring  can  of  course  be  used. 

The  guiding  pulley  over  which  the  cord  of  the  paper  cylinder  is 
led  can  be  adjusted  to  any  direction  by  a  set-screw  as  shown  in  the 
illustrations.  The  lead  pencil  should  be  hard  to  insure  sharp  lines. 
Only  fine  watch  oil  must  be  used  to  prevent  gumming.  After  using 
take  the  indicator  apart  and  clean  carefully. 

When  no  provision  has  been  made  for  attaching  the  indicator, 
holes  must  be  drilled  and  tapped  in  the  side  of  the  cylinder  near 
each  end,  so  that  when  the  piston  is  at  the  end  of  its  strokes,  the 
holes  shall  be  about  midway  in  the  clearance  space  left. 

If  obstructed  by  the  piston,  steam  will  be  cut  off  from  the  instru- 
ment. The  tap  should  be  for  half-inch  pipe.  Chips  from  drilling 
should  be  blown  out  of  the  cylinder  by  turning  on  steam.  If  clear- 
ance space  is  too  small,  drill  directly  into  the  head.  Cocks  should 
obstruct  the  passage  of  steam  as  little  as  possible.  By  using  a  "three 
way  "  cock  leading  to  both  ends  of  the  cylinder,  one  indicator  will 
serve  for  taking  diagrams  from  both  ends  by  admitting  steam 
accordingly.  This  will  do  away  with  changing  the  cord  connection 
rotating  the  paper  cylinder.  The  motion  of  this  cylinder  could  be 
got  by  attaching  the  cord  wound  around  the  base  to  the  crosshead 
of  the  engine  piston.  Manifestly  this  would  afford  too  great  motion 
and  would  cause  the  paper  cylinder  to  revolve  several  times.  The 
stroke  of  the  engine  must  be  reduced  by  the  intervention  of  some 
combination  of  reducing  levers. 


82  The  Engine  and  Its  Parts. 

Numerous  devices  exist  for  this  reduction,  the  chief  point  being 
that  the  motion  of  the  piston  crosshead  should  not  be  in  the  least 
distorted  by  the  intervening  mechanism,  as  is  too  frequently  the 
case.  The  most  correct  and  convenient  device  which  transmits  the 
true  motion  of  the  crosshead  to  the  paper  cylinder  is  the  Bacon 
Pantograph,  of  which  we  give  illustrations  in  Figs.  46  and  47. 

The  following  description  of  method  of  attaching  the  indicator 
cord  by  "  Chordal "  appeared  in  the  American  Machinist : 

"  It  is  manufactured  by  the  American  Steam  Gauge  Company  of 
Boston.  It  consists  of  a  lazy-tongs  system  of  levers.  The  long 


FIG.  46. — THE  BACON  PANTOGRAPH. 

levers  are  of  cherry  wood,  16  in.  between  centers,  i^  by  -fa;  those 
marked  B  being  single  strips,  and  those  marked  A  being  double  strips. 
This  makes  the  thing  very  stiff  and  substantial.  The  pivots  should 
be  got  up  in  good  style,  and  the  pivot  holes  bushed.  The  hitch 
strip  G  should  be  arranged  so  that  it  may  be  shifted  in  the  holes  E, 
and  bring  a  hitch  pole,  F,  in  a  line  passing  through  pivots  C,  D.  The 
end  pivots  C  and  D  should  have  a  projection  below  of,  say,  2  in.,  with 
the  end  somewhat  pointed.  Any  one  who  attempts  to  make  one  of 
these  things  will  have  fun.  The  least  variation  in  the  location  of  the 
pivot  holes  will  cause  the  levers  to  refuse  to  act.  No  dimensions 
are  essential;  and  if  the  thing  will  close  up  nicely,  and  open  out 
nicely,  it  is  all  right;  if  it  won't  do  both,  it  is  all  wrong.  The  engine 
crosshead  must  have  a  vertical  hole  in  it  somewhere,  so  that  pivot  C 


84  The  Engine  and  Its  Parts. 

can  be  dropped  into  it.  A  stake  must  be  set  in  the  floor  near  the 
guides,  having  a  socket  for  the  pivot  D  in  its  top.  The  stake  socket 
must  be  level  with  the  crosshead  socket,  and  must  be  directly 
opposite  the  crosshead  socket  when  the  latter  is  at  mid-stroke.  The 
indicator  cord  is  hooked  to  the  center  peg  F,  and  the  stake  should 
set  at  such  a  distance  from  the  guides  that  the  cord  will  lead  off 
parallel  with  the  guides.  Otherwise  a  guide  pulley  will  be  called  for. 
When  this  ring  is  in  motion,  every  point  on  a  line  cutting  C  D  has  a 
true  motion  parallel  with  the  guides,  varying  in  distance  from  nothing 
at  D  to  length  of  a  stroke  at  C.  It  is  only  necessary  to  hitch  the  cord 
at  a  point  on  this  line  which  will  give  the  right  amount  of  motion  to  the 
cord.  This  point  will  be  near  D,  and  within  the  range  of  adjust- 
ment of  the  strip  G.  This  is  as  neat  a  device  as  could  be  wished 
for.  I  have  seen  men  hook  on  to  an  engine  running  at  a  good  gait, 
without  stopping.  For  a  permanent  rig  on  a  nice  engine,  the  stake 
can  normally  support  a  neat  table  top  for  oil  cans  and  waste." 

CONDENSERS  are  supplied  to  all  large  yacht  engines,  but  steam 
launches  are  still  generally  worked  against  the  pressure  of  the  atmos- 
phere. In  small  boilers  it  is  easier  to  obtain  the  requisite  strength  to 
withstand  high  pressure,  and  it  is  generally  deemed  preferable  to 
carry  from  10  to  12  Ibs.  more  pressure  in  the  boiler  than  to  go  to  the 
expense  and  weight  of  attaching  a  condenser  with  its  pumps  and 
piping.  Fresh  water  for  feed  can  be  obtained  in  a  launch  at  short 
intervals,  and  by  occasional  blowing  off,  a  small  supply  of  fresh 
water  will  keep  the  density  low  enough  for  short  runs,  even  if  the 
boiler  be  filled  from  the  sea.  For  long  runs  and  sea  cruising,  how- 
ever, a  condenser  is  a  necessary  part  of  the  marine  engine.  For  the 
development  of  a  given  power  the  boiler  pressure  can  be  lower  by 
just  the  amount  removed  from  the  exhaust  side  of  the  piston  by 
working  against  the  partial  vacuum  produced  by  condensing  the  ex- 
haust steam  in  a  special  chamber  for  that  purpose. 

The  steam,  having  done  its  work  in  the  cylinder,  is  allowed  free 
escape  through  a  pipe  of  large  sectional  area  leading  to  the  condenser. 
There  it  is  brought  in  contact  with  cold  water  pumped  in  from  the 
sea  by  the  "circulating  pump,"  and  precipitated  or  condensed  into 
water,  forming  a  partial  vacuum,  as  water  will  occupy  only  a  sixteen 


The  Engine  and  Its  Parts.  85 

hundred  and  forty-second  part  of  the  volume  filled  by  an  equal  weight 
of  steam  at  atmospheric  pressure. 

The  earlier  condensers  were  of  the  simplest  kind,  a  jet  of  cold 
water  being  forced  into  a  cast  iron  chest  into  which  the  exhaust  was 
received.  The  jet  was  taken  from  the  sea,  hence  the  condensed 
steam  mingled  with  it,  and  being  pumped  back  into  the  boiler, 
supplied  water  almost  as  salt  as  that  of  the  sea  itself.  In  vessels 
navigating  fresh  rivers  or  lakes,  the  jet  accomplished  all  that  was 
desired,  and  this  form  is  still  commonly  used  in  steamboats  which 
fill  up  with  fresh  water  at  stated  periods  at  the  dock.  But  for  sea- 
going purposes  or  irregular  cruising,  where  the  boiler  water  cannot 
be  changed  as  required,  a  superior  arrangement,  known  as  the  "  sur- 
face condenser,"  has  displaced  the  jet  altogether.  It  was  not  until 
1862  that  this  new  form  received  the  attention  it  deserved.  Numerous 
patterns  have  since  been  evolved,  differing  in  mechanical  details,  but 
all  operating  on  the  same  plan. 

At  first  the  exhaust  was  passed  into  a  series  of  copper  or  brass 
tubes  in  the  casing  of  the  condenser,  the  cooling  water  being  allowed 
to  drip  down  through  a  sprinkling  plate  above.  The  steam  was  con- 
densed in  the  tubes  and  ran  into  a  collecting  well,  from  which  it  was 
returned  to  the  boiler  by  means  of  the  "air  pump,"  so  called  from 
the  fact  that  it  draws  both  water  and  air  from  the  condenser.  At 
present,  however,  the  method  is  reversed,  the  cooling  sea  water  being 
forced  through  the  tubes  by  a  "circulating  pump,"  and  the  steam 
condensing  in  the  spaces  between  the  tubes  by  coming  in  contact 
with  their  cool  surfaces.  The  condensed  steam  drops  to  the  bottom, 
whence  it  is  withdrawn  by  the  air  pump  and  forced  either  directly  to 
the  boiler  as  feed,  or  collected  in  an  intermediate  receiver  called  the 
hot  well,  where  it  serves  as  suction  for  the  feed  pump. 

The  Lighthall,  though  extensively  used  in  the  merchant  service 
and  English  yachts,  is  now  being  superseded  by  the  Wheeler  Improved 
Surface  Condenser  with  independent  air  and  circulating  pumps, 
capable  of  being  worked  and  regulated  without  regard  to  the  main 
engine.  The  objections  to  the  ordinary  surface  condenser  are  the 
unequal  expansion  and  contraction  of  tubes,  breaking  or  rupture  of 
tube  heads,  leaking  of  packings  at  head  and  the  "crawling "of  tubes 


86  The  Engine  and  Its  Parts. 

partially  or  entirely  out  of  their  heads,  unequal  distribution  of  steam 
over  cooling  surface,  so  that  parts  of  condenser  are  hot  while  other 
parts  are  cold,  insufficient  vacuum,  condensed  steam  (feed  water)  not 
as  hot  as  it  should  be,  and  the  liability  of  the  circulating  water  to 
leak  into  the  steam  space  and  mix  with  the  water  of  condensation — 
thus  defeating  the  objects  for  which  surface  condensers  are  intended. 
The  Wheeler  Surface  Condenser  has  none  of  the  above  objections, 
and   combines   the    necessary  theoretical  qualifications  with   sound 
practical  features.     The  tubes  are  so  arranged  that  they  are  free  to 
expand  and  contract  without  the  use  of  packings  of  paper,  wood  or 
similar  materials;  there  are  no  ferrules,  followers,  washers  or  pack- 
ings of  any  kind  employed.     Plain  screw  joints  are  used — the  sim- 
plest, most  durable  and  efficient  tube  fastening  possible,  and  always 
tight.    The  tubes  are  straight,  of  seamless  brass  tubing,  tinned  inside 
and  outside.     They  can  be  easily  taken  out  and  thoroughly  cleaned, 
as  their  form  and  the  means  of  fastening  them  permit  of  this  being 
readily  done.     The  tube  heads  do  not  have  to  be  removed  from  the 
condenser  for  the  cleaning  or  repairing  of  the  tubes.     The  pressure 
(and  likewise  the  temperature)  of  the  exhaust  steam  as  it  enters  the 
condenser  is  reduced  to  a  minimum,  and  is  then    uniformly  dis- 
tributed over  the  cooling  surface.     This,  together  with  a  perfect  cir- 
culation of  water  in  the  tubes,  produces  a  more  uniform  temperature 
in  the  condenser,  making  one  portion  as  efficient  as  another,  and 
economizing  the  amount  of  cooling  surface  and  circulating  water. 
The  water  of  condensation  passes  from  the  condenser  at  the  hottest 
temperature  possible.     The  circulation  is  active  and  thorough,  con- 
sequently a  smaller  amount  of  circulating  water  is  required;   this 
feature  gives  a  saving  in  the  capacity  and  power  necessary  to  work 
the  pump. 

Referring  to  the  accompanying  sectional  illustration,  the  opera- 
tion of  the  condenser  is  as  follows  : 

The  exhaust  steam  from  the  engine  entering  the  condenser  by  the 
nozzle  A,  comes  first  in  contact  with  the  perforated  scattering  plate 
O,  which  protects  the  central  portion  of  the  upper  tubes  from  the 
deteriorating  effect  of  the  direct  impingment  of  the  steam. 

The   steam   expanding   in   the   spacious   top   of   the   condenser, 


88 


The  Engine  and  Its  Parts. 


reduces  its  pressure  and  temperature  before  it  comes  in  contact  with 
the  cold  tubes.  The  steam  as  soon  as  condensed,  gravitates  to  the 
bottom,  and  passes  out  by  the  nozzle  B  to  the  air  pump. 

It  will  be  noticed  that  there  is  ample  room  in  the  bottom  of  con- 
denser for  the  water  of  condensation,  so  that  it  cannot  come  in 
contact  with  the  cold  tubes  and  become  chilled ;  the  hot  water 
therefore  passes  out  at  the  highest  possible  temperature — according 
to  the  vacuum  carried. 

The  circulation  of  the  condensing  or  cooling  water  is  as  follows : 
It  is  pumped  into  the  compartment  F  through  the  nozzle  C,  and 


FIG.  49. — SECTION  THROUGH  LAUNCH. 


A.  After  end  of  condenser. 

B.  Circulating  pump. 


C.  Feed  pump. 

D.  Combination  pump  steam  cylinder.1 


enters  the  small  tubes  as  shown  by  the  arrows.  After  traversing  the 
9mall  feubes,  the  water  returns  through  the  annular  spaces  between 
the  small  and  large  tubes  of  the  upper  section  in  the  same  manner, 
and  finally  passes  out  of  condenser  by  the  discharge  nozzle  D. 

The  small  tube  is  expanded  into  a  screw-head  which  latter  screws 
into  the  head  of  the  casting  at  H.  This  small  tube  ends  within  a 
few  inches  of  the  cap  at  the  loose  end  of  the  large  tube,  thereby 
giving  ample  space  for  the  water  to  reverse  its  direction  before 
flowing  back  through  the  annular  space  between  the  two  tubes. 
The  end  of  the  large  tube  screws  into  the  casting  head  D  G,  so  that 


The  Engine  and  Its  Parts.  89 

coarse  deep  threads  and  a  screw-driver  slot  can  be  cut,  which  admits 
a  tool  for  screwing  up  or  unscrewing  tubes  from  the  tube  heads. 
When  necessary  to  remove  the  tubes  for  cleaning  or  repairs,  both 
small  and  large  tubes  can  be  drawn  out  from  the  same  end  of  the 


FIG.  50. — PLAN  OF  CONDENSER  AND  CONNECTIONS. 


A.  Condenser. 

B.  Circulating  pump. 

C.  Feed  pump. 

D.  Combination  pump  steam  cylinder. 

E.  Suction  to  circulating  pump. 

F.  Delivery    from    circulating    pump   to    con- 

denser. 


G.     Outboard  delivery  of  circulation  water. 
H.     Exhaust  steam  from  cylinder  to  condenser0 
J.      Suction  from  condenser  to  feed  pump. 


M. 


Feed  to  boiler  from  feed  pump. 
Suction  from  tank  to  feed  pump. 


condenser.  After  removing  the  small  tube  the  large  tube  is 
unscrewed  and  drawn  through  the  hole  left  vacant  by  the  screw 
head  of  the  small  tube — this  hole  being  a  little  larger  than  the  thick 
end  of  the  large  tube. 


90  The  Engine  and  Its  Parts. 

The  illustrations  given  are  taken  from  condensers  of  very  large 
capacity.  For  steam  yachts,  the  same  principles  and  arrangements 
are  followed,  but  the  weight  and  size  are  much  reduced.  Thus,  for  a 
40  H.  P.  engine,  the  body  of  the  condenser  is  a  12  in.  pipe  7  ft.  long. 
The  Wheeler  condenser  with  pumps  complete  will  weigh  less  than 
the  usual  marine  condenser  without  pumps  and  piping,  and  in 
launches  can  be  set  up  under  the  thwarts  out  of  the  way. 

The  advantages  arising  from  the  use  of  surface  condensation  are 
the  increased  power  derived  from  working  against  a  partial  vacuum 
on  the  exhaust  side  of  the  piston  instead  of  against  the  atmosphere, 
the  furnishing  of  distilled  water  to  the  boilers  preventing  loss  of 
heat  by  frequent  blowing  off  and  scaling  at  high  pressures. 

In  many  small  American  yachts  an  "outboard  condenser"  has 
been  adopted.  This  consists  simply  of  a  pipe  running  fore  and  aft 
along  the  garboards  on  the  outside  of  the  vessel.  In  point  of  sim- 
plicity, cheapness  and  saving  of  weight  this  plan  is  far  ahead  of  the 
old  style  "Lighthall"  condenser  with  its  heavy  cast-iron  casing  and 
rigid  tubes,  and  is  being  extensively  adopted.  Being  in  contact 
with  the  sea,  its  whole  surface  is  subject  to  the  same  cooling  tem- 
perature, whereas  in  the  ordinary  condenser  greater  surface  must  be 
provided  to  allow  for  the  heating  of  the  injection  water  as  it  pro- 
ceeds through  the  tubes.  The  circulating  pump  is  also  abolished,  as 
also  the  "injection"  and  "outboard  delivery"  valves  and  piping 
attendant  upon  the  use  of  the  pump.  The  Hancock  "ejector"  also 
takes  the  place  of  the  air-pump  at  a  great  saving  in  weight,  and 
the  same  instrument  will  deliver  the  condensed  steam  to  the  hot 
well  or  tank  from  which  the  boiler  is  supplied. 

In  large  yachts  a  series  of  outboard  pipes  oblige  the  exhaust  to 
pass  fore  and  aft  two  or  three  times,  insuring  large  cooling  surface 
in  small  pipes.  They  have  a  block  of  wood  tapered  away  to  a  point 
at  their  forward  end.  No  power  is  lost  working  a  circulating  pump 
and  no  deleterious  acids  from  the  decomposition  of  lubricants  and 
the  copper  or  brass  tubes  or  the  "packing"  of  the  latter  are  returned 
to  the  boiler,  as  is  the  case  with  the  regular  surface  condenser. 

The  "outboard"  condenser  on  anything  larger  than  launch  or 
river  yacht,  is  always  in  the  nature  of  a  makeshift  and  an  obstruction 


The  Engine  and  Its  Parts.  91 

to  the  free  closing  of  the  water  in  the  vessel's  run  and  its  access  to 
the  screw.  The  liability  to  accident  is  always  present  and  the 
expense  of  docking  for  repairs  may  more  than  counterbalance 
saving  in  first  cost.  It  is  not  to  be  counselled  for  cruising  yachts 
which  will  frequently  find  themselves  beyond  the  reach  of  docking 
facilities.  For  reliable  service  the  Wheeler  condenser  is  to  be  pre- 
ferred. In  some  recent  torpedo  boats  the  circulating  water  is 
forced  by  the  speed  of  the  vessel,  the  orifice  of  a  pipe  projecting 
forward  through  the  boat's  skirf,  the  travel  of  the  vessel  driving  the 
sea  water  into  the  pipe.  This  is  supplemented  by  a  steam  jet  when 
the  speed  is  insufficient. 

In  all  yacht  engines,  the  surface  condenser  has  hitherto  been 
made  to  form  part  of  the  engine  framing,  as  will  be  seen  from  illus- 
trations in  these  pages.  This  is  still  a  feature  of  all  English  marine 
engines.  But  the  latest  American  improvements,  such  as  the 
Wheeler  condenser,  are  independent  attachments,  which  is  pre- 
ferable. For  lake  and  fresh  water  river  service,  the  jet  will  take  the 
place  of  the  surface  condenser,  as  no  objection  exists  to  mingling  the 
injection  water  with  the  condensed  steam. 

The  use  of  the  condenser  enables  the  engine  to  work  against  a 
vacuum,  and  is  therefore  desirable,  even  if  the  air  pump  sends  the 
'  contents  overboard  instead  of  to  a  hot-well.  By  using  the  contents 
over  again,  however,  as  feed  for  the  boiler,  there  will  be  a  saving  of 
heat  as  the  condensed  steam  will  impart  its  heat  to  the  injection  and 
leave  it  warmer  than  cold  feed  pumped  in  from  the  river.  If  the 
latter  be  muddy,  the  feed  from  the  hot-well  will  be  partly  purified 
through  the  distilling  operation  of  the  condenser,  and  less  dirt  will 
be  fed  to  the  boiler.  The  jet  is  lighter,  simpler  and  cheaper  than 
the  surface  condenser  necessary  in  navigating  salt  seas. 

A  compact  and  excellent  arrangement  is  shown  in  the  illustrations 
of  the  Worthington  Independent  Jet  Condenser.  The  injection  can- 
not be  drawn  over  into  the  steam  cylinder,  and  the  danger  of  flood- 
ing is  thus  avoided  without  the  use  of  floats,  check-valves  or  auto- 
matic contrivances. 

Should  the  pump  from  any  cause  be  stopped  while  the  main 
engine  is  at  work,  the  vacuum  would  be  immediately  destroyed,  and 


FIG.  51.— THE  WORTHINGTON  INDEPENDENT  CONDENSER. 

[92] 


The  Engine  and  Its  Parts. 


93 


the  injection  water  stop  flowing,  as  the  latter  is  not  forced  by  a 
special  circulating  pump,  but  is  drawn  in  by  the  suction  of  the  air 
pump.  No  "  head  "  is  required  to  the  supply  for  the  same  reason, 
as  the  air  pump  will  lift  water  from  any  point  within  the  limits  of 
suction. 

In  the  illustration,  the  exhaust  steam  from  cylinder  passes  in  at 
the  elbow  on  top.  The  injection  enters  through  the  valve  above  the 
elbow,  and  passes  over  a  cone  in  the  pipe,  provided  with  wings  which 
separate  the  water  into  a  shower  of  spray  to  insure  complete  admix- 
ture with  the  steam.  The  cone  is  adjustable  by  the  handwheel  shown 
in  the  cut,  and  all  strainers  are  done  away  with,  so  that  liability  to 
choke  up  is  removed.  By  simply  lowering  the  cone,  any  obstructing 
article  introduced  with  the  injection  can  be  freed.  The  injection 
water,  after  it  has  done  its  duty  in  the  condenser,  can  be  forced,  if 
required,  to  a  tank  or  hot-well  at  an  elevation,  if  it  is  not  to  be  dis- 
charged through  a  sea  valve.  This  condenser  has  been  fitted  with 
great  success  to  many  yachts,  notably  to  the  steamer  built  for  Mr. 
David  Bell  of  Buffalo,  whose  engine  is  of  the  compound  type,  with 
cylinders  9  and  12  in.  by  12  in.  stroke.  The  exhaust  from  the  steam 
cylinders  of  the  pump  is  turned  into  the  condenser  by  a  pipe,  so  that 
the  air  pump  will  also  work  against  a  vacuum. 


No.  of  Con- 
denser. 

Diameter  of 
Steam 
Cylinders. 

Diameter  of 
Water 
Cylinders. 

Length  of 
Stroke. 

Diameter  of 
Engine 
Exhaust 
Pipe. 

Diameter  of 
Injection 
Pipe. 

Diameter  of 
Delivery 
Pipe. 

I 

3 

4 

6 

4 

2K 

2 

2 

4 

5^ 

6 

5 

3 

3 

3 

5 

7 

10 

6 

4 

4 

4 

5 

7 

IO 

7 

4 

4 

5 

6 

IO 

8 

5 

6 

6 

8K 

10 

3                   5 

5 

A  feed  water  heater  can  be  introduced  between  engine  cylinder 
and  the  condenser,  so  that  the  heat  from  the  exhaust  steam  can  be 
utilized  in  raising  the  temperature  of  fresh  feed,  which  is  forced 
through  the  piping  of  the  heater  by  the  feed  pump. 


94 


The  Engine  and  Its  Parts. 


The  state  of  the  vacuum  is  indicated  by  a  mercury  vacuum  gauge 
constructed  as  explained  for  steam  pressure,  but  reversed  by  connect- 
ing the  basin  with  the  condenser  and  commencing  from  the  bottom 
with  the  scale.  According  to  the  presence  or  absence  of  pressure  in 
the  condenser,  the  mercury  in  the  basin  will  ascend  the  tube  until 
balance  is  established.  A  rise  of  two  inches  in  mercury  is  equal  to 
one  pound  per  square  inch,  and  would  indicate  one  pound  more 


FIG.  52. 


pressure  in  the  condenser  than  a  perfect  vacuum.  A  rise  to  28  on 
the  scale  would  indicate  a  difference  of  about  14  Ibs.  between  the 
pressure  inside  and  outside  the  condenser.  The  vacuum  would  be 
— 14,  that  is,  14  Ibs.  below  atmosphere.  It  is  usual  to  designate  the 
vacuum  by  the  scale  of  inches;  in  this  case  it  would  be  called  28. 
The  glass  need  not  be  30  in.  long,  as  the  engine  is  supposed  to  main- 
tain at  least  1 6  to  17  in.  vacuum,  so  that  14  in.  will  be  tube  enough  to 
cover  the  range  likely  when  working  the  engines.  Vacuum  gauges 
are  also  frequently  made  on  the  Bourdon  principle.  It  is  customary 


The  Engine  and  Its  Parts.  95 

to  have  all  gauges  in  the  engine  room  set  in  one  frame,  so  that  ready 
inspection  can  be  made.  Such  a  frame  will  include  a  clock,  steam 
and  vacuum  gauges  and  a  revolution  counter,  showing  the  number 
of  turns  made  by  the  shaft.  From  the  latter  the  "  slip  "  of  the  screw 
is  ascertained,  being  the  difference  between  the  distance  the  vessel 
would  have  steamed  had  the  screw  worked  in  a  solid  and  the  lesser 
distance  actually  made.  The  speed  of  the  engine  is  also  regulated 
by  the  counter.  It  is  operated  by  levers  connecting  with  the  engine, 
and  a  worm  and  series  of  geared  wheels  inside  the  case. 


V. 

THE     SCREW. 

IT  is  not  necessary  to  include  the  paddle-wheel  as  an  instrument 
of  propulsion,  for  it  is  obsolete  in  yacht  building  practice.  A 
few  side-wheel  steam  yachts  are  still  in  commission  in  British  waters, 
but  the  superior  efficiency  of  the  screw  and  its  adaptability  to  the 
lightest  draft  are  so  well  proven  that  the  paddle-wheel  calls  for  no 
attention.  With  the  high  piston  speeds  now  becoming  all  but 
universal,  the  paddle-wheel  is  out  of  question,  even  if  it  were  not 
objectionable  on  other  scores,  such  as  great  weight,  cumbrous  boxes 
overhanging  the  side,  loss  due  to  oblique  action  of  blades  and 
irregular  dip  in  a  seaway,  etc.  In  theory  the  feathering  paddle- 
wheel,  in  which  the  blades  are  retained  nearly  in  a  vertical  position 
during  the  revolution  by  means  of  an  eccentric  on  the  shaft  with 
arms  to  the  swinging  blades,  is  the  most  efficient  propeller  in  smooth 
water.  A  wheel  can  be  used  smaller  than  when  the  blades  are  fixed, 
as  in  the  common  radial  wheel,  as  the  oblique  action  upon  first 
dipping  and  finally  emerging  from  the  water  is  done  away  with. 
The  feathering  wheel  is  therefore  adopted  where  higher  piston  speed 
is  desired,  and  is  more  suitable  for  rough  water.  But  the  weight  and 
complication  of  the  feathering  gear  and  its  friction  are  objections 
which  leave  the  advantage  with  the  screw. 

The  operation  of  a  screw  can  be  likened  to  that  of  a  common 
carpenter's  screw  progressing  into  wood  in  answer  to  rotary  force 
applied  through  the  screw  driver.  In  a  vessel  the  water  takes  the 
place  of  the  wood,  being  really  an  endless  nut  in  which  the  propeller 


The    Screw.  97 

revolves.  If  we  cut  a  longitudinal  piece  from  the  carpenter's  screw 
we  have  a  representation  of  the  common  or  "  true  screw "  of  ship 
propulsion.  It  is,  however,  not  necessary  in  practice  to  have  a  sec- 
tion so  long  that  the  thread  shall  wind  once  round  the  central  spindle 
or  hub.  A  short  part  of  a  complete  revolution  is  enough,  as  resist- 
ing area  to  the  water  must  be  preserved.  The  efficiency  of  the  screw 
is  further  increased  by  introducing  one  or  more  intermediate  threads, 
as  if  we  wound  additional  spirals  around  the  carpenter's  screw.  Each 
blade  of  the  ship  screw  represents  a  short  piece  of  as  many  threads 
as  there  are  blades.  The  distance  along  the  axis  of  a  screw  required 
to  complete  one  convolution  of  the  thread  is  the  "pitch."  In  a 
three-bladed  screw  three  threads  are  wound  about  the  axis  within  the 
same  distance  along  the  axis. 

The  "axis"  is  the  imaginary  fore-and-aft  center  line  through  the 
shaft  upon  which  the  threads  are  wound. 

The  "  radius  "  of  a  screw  is  half  the  diameter  or  the  distance  from 
center  of  shaft  to  periphery  of  blade. 

The  "  length  "  of  a  screw  is  the  fore-and-aft  distance  taken  up  by 
the  blade,  and  varies  with  the  pitch  and  extent  of  periphery  or  dis- 
tance along  the  outer  edge  of  the  thread. 

The  edge  of  the  blade  which  strikes  the  water  first  is  the  "  leading 
edge,"  the  after  one  being  the  "following  edge." 

When  the  face  of  the  blade  has  a  curvature  increasing  aft  from  the 
leading  to  the  following  edge,  it  is  said  to  have  an  "  expanding  pitch 
longitudinally."  That  is  to  say  the  pitch  of  the  thread  has  been 
increased,  so  that  the  following  part,  finding  the  water  already  driven 
astern  by  the  leading  part,  shall  preserve  its  effect  upon  the  escap- 
ing column. 

When  the  pitch  of  the  periphery  differs  from  that  of  the  blade 
near  the  hub,  the  screw  has  a  varying  pitch  radially.  At  the  hub 
the  blade  is  moulded  more  nearly  fore-and-aft  in  line  with  the  vessel's 
keel,  to  supply  metal  enough  for  strength.  If  the  same  pitch  were 
carried  up  to  the  periphery,  the  screw  would  be  too  "coarse,"  and 
would  churn  the  water  without  driving  it  astern.  The  pitch  at  the 
hub  is  therefore  diminished  gradually  toward  the  periphery,  and  the 
blade  made  wider  where  it  is  most  efficient.  To  do  away  with  the 


98 


The    Screw. 


useless  churning  near  the  axis,  the  central  part  of  some  screws,  as  in 
the  Griffiths  propeller,  is  filled  in  by  a  large  spherical  hub,  only  the 
effective  portion  of  the  blades  projecting.  The  pitch  toward  the 
axis  is  also  made  coarser  to  allow  for  the  slower  speed  near  the 
center.  A  given  pitch  and  speed  may  be  effective  at  the  periphery, 
but  the  same  pitch  at  a  slower  speed  would  fail  to  do  its  share  of 
propelling. 


FIG.  53. 

No.  i.  Towing  wheel  with  large  area.     No.  2.  Four-bladed  speedwheel  for  yachts. 
No.  3  and  4.   Two  and  three-blade  wheels  for  launches,  according 
to  practice  of  Chas.  P.  Willard  &  Co.,  Chicago. 


The  after  face  of  a  screw  is  called  the  "driving  face,"  the  forward 
surface  being  the  "dragging  face."  This  face  is  moulded  with  a 
view  to  supplying  the  requisite  metal  to  the  blade,  and  its  form  is 
governed  by  that  of  the  driving  face.  Chief  Engineer  F.  B.  Sher- 
wood, U.  S.  N.,  reversed  the  screw  while  testing  a  Herreshoff  built 


The    Screw. 


99 


yacht  and  obtained  equal  results  from  the  convex  or  dragging  face 
as  from  the  driving  face,  due  no  doubt  to  the  close  similarity  of  the 
faces  in  a  small  screw  with  thin  blades. 

The  "oblique  area"  of  a  screw  is  the  sum  of  the  actual  areas  of 
the  blades.  The  "effective  area"  is  the  area  of  the  blades  projected 
upon  a  thwartship  plane.  The  "disc  area"  is  the  area  of  the  circle 
described  by  the  screw's  diameter.  The  "helix"  is  the  spiral 
described  by  a  point  on  the  blade  during  its  onward  progression.  If 
the  screw  were  working  in  a  solid,  this  would  correspond  to  the 
thread. 

The  "center  of  pressure"  of  a  screw  is  located  from  the  axis  at  a 
distance  equal  to  the  radius  of  a  circle  having  half  the  disc  area. 
The  pressure  outside  of  a  circle  drawn  with  such  a  radius  will  equal 
that  within  the  circle,  providing  the  pitch  is  constant  from  hub  to 
periphery,  so  that  the  velocity  of  the  columns  of  water  driven  aft 
will  be  the  same  all  through. 

The  "apparent  slip"  of  a  screw  is  the  difference  between  the 
speed  of  the  propeller  and  that  of  the  ship.  If  the  screw  worked  in 
a  solid  instead  of  a  yielding  medium,  the  two  speeds  would  be  alike ; 
but  as  the  water  slips  away  from  the  screw  it  follows  that  the  screw 
must  make  an  increased  number  of  revolutions  for  the  production 
of  a  given  speed  in  the  vessel. 

The  reacting  pressure  upon  the  screw  is  transferred  through  the 
shaft  to  special  bearings  made  to  receive  this  pressure  or  "thrust," 
the  bearings  being  known  as  the  "  thrust  bearings  "  in  contradistinc- 
tion to  the  ordinary  bearings  which  support  the  shaft  in  line.  The 
amount  of  thrust  is  measured  by  a  dynamometer,  an  instrument  con- 
taining levers  and  weights  with  scale.  The  thrust  multiplied  into 
the  distance  the  vessel  moves  in  a  unit  of  time,  shows  the  actual 
power  utilized  in  driving  the  ship. 

If  all  the  power  applied  to  the  piston  were  transmitted  to  the 
water  through  the  propeller,  the  total  pressure  upon  piston  and  the 
thrust  of  the  propeller  would  be  equal.  The  theoretical  thrust  in 
pounds  would  therefore  be: 

Total  unbalanced  pressure  on  piston  in  Ibs.  X2  stroke  in  ft.  X  No.  of  Revs,  per  Min. 
Pitch  of  propeller  in  ft.  X  No.  of  Revs,  per  Min. 


i  oo  The    Screw. 

The  difference  between  this  and  the  actual  thrust  as  per  dyna- 
mometer, shows  the  amount  lost  in  friction  of  engines,  propeller  and 
load,  resistance  of  edges  of  propeller  blade,  working  air  and  circu- 
lating pumps,  etc.  The  loss  from  slip  is  independent  of  this. 
Apparent  slip  is  expressed  in  percentage  of  speed.  If  the  vessel  be 
moving  at  8  knots  and  the  screw  at  10,  then 

10 —  8 

X  100  =  20  per  cent.  slip. 

Should  the  after  lines  of  a  vessel  be  so  full  as  to  draw  a  current 
in  the  wake  of  the  vessel  in  the  direction  in  which  she  is  moving,  it 
might  be  possible  that  the  vessel  would  move  faster  over  the  ground 
than  can  be  accounted  for  by  the  revolutions  of  the  screw,  as  the  latter 
is  working  against  a  fluid  with  onward  motion  and  gains  proportion- 
ately in  its  thrust.  This  phenomenon  is  termed  "negative  slip,"  a 
term  which  is  only  one  of  comparison  to  express  the  relation 
between  speed  of  ship  and  screw.  In  truth  no  screw  can  have 
negative  slip  of  its  own  making.  This  so-called  slip  represents  a 
wasteful  expenditure  in  power  in  producing  the  following  current 
and  is  seldom  observed.  In  yachts  with  clean  runs  it  never  occurs. 

"•Real  slip,"  the  velocity  with  which  a  column  of  water  is  thrown 
astern  from  the  screw,  is  not  to  be  regarded  as  an  evil  characteristic, 
but  on  the  contrary,  indicates  the  amount  of  beneficial  work  the 
screw  is  accomplishing.  Absence  of  real  slip  is  a  sign  of  inefficiency. 
Water  being  a  yielding  medium,  and  action  and  re-action  always 
alike,  it  follows  that  the  thrust  transmitted  to  the  bearings  will  vary 
with  the  velocity  with  which  water  is  driven  astern  by  the  screw. 

If  we  imagine  the  pitch  of  a  screw  steadily  diminished,  its  work 
for  a  given  number  of  revolutions  will  decrease  *as  also  the  velocity 
with  which  the  water  is  driven  astern.  Ultimately  when  the  screw 
has  been  flattened  out  into  a  plain  thwartship  disc,  there  will  be  no 
slip  at  all  and  no  thrust,  and  the  vessel  would  remain  stationary  in 
absence  of  slip.  But  as  the  pitch  is  decreased  less  power  will  be 
required  to  give  it  rotation.  Starting  with  equal  steam  it  follows 
that  a  refinement  of  pitch  permits  a  greater  number  of  revolutions, 
by  which  the  speed  of  the  water  driven  astern  will  be  accelerated, 
and  in  that  way  make  up  for  the  finer  pitch. 


The    Screw.  101 

From  this  the  conclusion  would  be  reached  that  fine  pitch  with 
increased  number  of  revolutions  is  equally  as  effective  as  coarse 
pitch  with  a  smaller  number  of  revolutions.  Withifl  limits  this?  is  the* 
case,  but  the  intermediate  loss  in  the  working  of  the  "engine  increases 
with  the  number  of  revolutions,  and  the  limit  would-  maker  ^self 
evident  in  practice.  Too  fine  a  pitch  driven  at  great  speed  will 
prove  an  error  on  one  side,  just  as  too  coarse  pitch  and  too  few 
revolutions  on  the  other.  The  only  safe  guide  is  the  comparison  of 
speeds  of  vessel  with  a  given  Indicated  Horse  Power.  The  w*hole 
problem  of  the  screw  in  practice  is  so  complex  and  its  efficiency  a 
compromise  between  so  many  antagonistic  requirements,  many  of 
which  we  cannot  measure  or  even  .follow  up,  that  nothing  but  actual 
test  can  be  depended  upon. 

In  general,  coarse  pitch,  large  area  and  slow  revolution  is  advan- 
tageous for  power  such  as  required  in  a  tug ;  but  for  speed,  finer 
pitch,  smaller  area  and  rapid  revolution  has  been  the  rule.  Of  late, 
however,  the  pitch  in  high  speed  vessels  has  been  increased  with  a 
gain  in  efficiency  but  a  greater  load  upon  the  engine,  as  the  num- 
ber of  revolutions  has  to  be  preserved  to  secure  some  of  the 
greater  speed  due  to  coarser  pitch.  The  blade  area  has  also  been 
reduced,  as  it  has  been  shown  that  the  leading  portion  is  the  effective 
part.  Too  small  area  will  increase  the  apparent  slip  and  too  large 
area  adds  to  the  friction  of  screw  and  wastes  power.  The  number 
of  blades  does  not  seem  to  affect  efficiency  of  the  screw,  but  three  or 
four  blades  work  smoother  than  two,  causing  less  vibration. 

Experiments  made  by  Messrs.  Yarrow  &  Co.,  on  one  of  their  high 
speed  torpedo  boats  in  1879,  warrant  certain  definite  conclusions. 
The  maximum  speed  reached  was  21.9  knots  or  over  25  land  miles. 

The  resistance  at  speeds  over  18  knots  does  not  increase  as 
rapidly  as  below  that  figure.  The  elasticity  of  propeller  blades 
greatly  increases  efficiency,  thin  blades  with  sharp  anterior  edge 
having  increased  the  speed  of  the  launch  from  17^  to  19  knots. 
Screws  showing  the  least  variation  in  slip  at  different  speeds  are  the 
most  efficient,  and  those  having  small  slip  at  low  speeds  are  the 
worst.  In  two  cases  like  results  were  obtained  from  two  screws, 
one  of  large  diameter  and  fine  pitch  and  the  other  of  small  diameter 


IO2  The    Screw. 

and  coarse  pitch.     Propellers  best  suited  for  high  speeds  are  not  as 

well  fitted  for  low  speeds.     Finally  that  there  is  a  propeller  best 

'suited  ft)*  the  *  conditions  and  failure  to  select  properly  may  have 

^important    earing,  upon  speed  and  even  affect  the  engine  perform- 


In  the  steam  yacht  Celia,  a  change  in  screw  accomplished  the 
same  speed  with  two-thirds  the  number  of  revolutions,  representing 
a  great  saving  in  wear  and  tear  to  the  machinery.  Propellers  placed 
under  the  body  of  the  vessel  do  not  give  as  good  results  as  if  placed 
abaft  the  sternpost.  By  extending  them  some  distance  beyond 


FIG.  54. — THE  THORNEYCROFT  SCREW. 

better  results  are  obtained  than  when  placed  nearer  to  the  post, 
probably  because  working  in  water  at  rest  and  not  interfering  with 
the  closing  up  cf  the  run. 

Summing  up  all  that  we  know  concerning  the  screw,  still  leaves  us 
without  precise  information  upon  which  to  formulate  directions,  and 
nothing  but  experiment  remains  to  discover  the  propeller  most  suit- 
able to  any  vessel  and  the  conditions  under  which  it  is  to  work. 
True  screws  have  given  as  good  results  as  any  of  the  modified 
forms. 

The  celebrated  Thorneycroft  propeller  has  "dished"  blades,  that 
is  bent  aft.  They  also  curve  outward  to  prevent  the  dispersion  of 
the  water  and  cause  it  to  be  thrown  aft  in  a  solid  column.  The 
screw  is  highly  advantageous  to  speed,  adding  a  seventh  over  the 


The    Screw.  103 

speed  obtained  with  the  Griffiths  and  other  ship  screws,  the  vibration 
being  also  reduced. 

The  Giant  propellers  of  Bliven  &  Co.,  New  York,  are  built  either 
two,  three,  or  four  blades,  ranging  in  diameter  from  15  in.  and  over, 
and  any  pitch  desired,  and  are  constructed  of  the  following  metals : 
Phosphor  bronze,  hydraulic  metal,  composition  valve  metal,  brass, 
annealed  steel,  cast  steel,  gun  metal,  car  spring  metal  or  cast  iron. 

The  pitch  is  a  true  one  from  the  periphery  to  the  hub,  and  every 
part  of  the  blade  travels  the  same  distance  ahead  in  each  revolution, 
thus  making  the  whole  surface  effective.  The  blade  has  a  relief  or 
compound  pitch,  one-third  of  the  distance  from  the  hub  to  the  end 


FIG.  55. — THE  "GIANT"  PROPELLER. 

of  the  blade,  by  reason  of  which  the  blades  near  the  hub  are  relieved 
of  the  dead  water  which  is  forced  out  behind  the  screw  and  com- 
pressed into  a  solid  mass.  When  the  screw  is  in  motion,  the  com- 
pressed water  behind  it  always  has  a  tendency  to  follow  the  screw, 
thus  compensating  for  loss  by  friction  and  slip. 

In  a  well  modeled  yacht  these  screws  will  save  much  loss  from 
friction  or  slip.  In  several  tests  made  under  different  conditions  in 
a  steam  yacht  with  one  of  these  screws,  6ft.  diameter,  9 'ft.  pitch,  a 
gain  of  three  per  cent,  was  made  over  the  speed  of  other  screws. 

They  leave  the  water  behind  comparatively  smooth,  and  do  not 
churn  it  up,  neither  does  a  vessel  propelled  by  this  style  of  screw 
have  a  tendency  to  settle  aft,  and  there  is  less  vibration  and  trem- 
bling on  the  vessel. 

The  Duncan  propeller,  made  by  Messrs.  Ross  &  Duncan,  of 
Glasgow,  Scotland,  is  very  favorably  known  for  its  excellent  results. 


IO4  The    Screw. 

The  blades  are  formed  to  a  combination  of  curves,  and  are  not  of 
the  plain  helical  construction.  The  chief  peculiarity  is  a  quick 
curvature  near  the  tips,  concave  to  the  driving  side,  as  can  be  seen 
in  the  illustration. 

This  form  was  adopted,  because  all  propellers  act  with  a  certain 
amount  of  slip,  necessary  to  give  the  propulsive  reaction,  and  there 
is  always  a  corresponding  amount  of  centrifugal  action  on  the  water. 


FIG.  56. — DUNCAN'S  PATENT  SCREW  PROPELLER. 

The  water  is  drawn  in  at  the  center  and  driven  outward  along  the 
blades.  If  the  propeller  were  replaced  by  a  plain  paddle  the  action 
would  be  purely  centrifugal  and  no  propulsive  effect  would  be  given. 
But  all  outward  motion  given  to  the  water  is  so  much  loss  of  power, 
as  it  is  not  driven  astern.  That  propeller  which  drives  the  water 
directly  aft  is  the  most  efficient.  The  curvature  mentioned  in  the 
Duncan  screw  is  introduced  with  a  view  to  counteracting  the  cen- 
trifugal tendency  and  to  convert  the  outward  motion  of  the  water 
into  an  equivalent  motion  aft. 


The    Screw.  105 

According  to  experiments  conducted  by  Chief  Engineer  Isherwood 
upon  the  steamer  Lookout,  he  estimated  that  70  per  cent,  of  the 
work  done  by  the  engines  was  utilized  in  propelling,  30  per  cent, 
being  the  intermediate  loss  between  cylinder  and  screw  due  to  the 
power  requisite  to  work  the  engine  and  its  waste. 

For  many  years  it  has  been  the  custom  to  apportion  the  power  of 
a  new  vessel  according  to  the  formula 

V3  X  D** 
I.  H.  P.  ' 

the  assumption  being  that  the  resistance  varies  as  the  square  of  the 
speed  (V)  and  the  power  required  to  overcome  it  as  the  cube  of  the 
speed.  Sometimes  the  area  of  midship  section  was  introduced 
instead  of  the  displacement  (D),  the  resistance  of  ships  of  similar 
form  but  of  different  dimensions,  being  supposed  to  vary  as  the  two- 
thirds  power  of  those  elements  at  any  given  speed,  and  the  effective 
power  directly  as  the  indicated  power,  I.  H.  P. 

Recent  years  have  shown  the  fallacy  of  such  assumptions,  unless 
within  narrow  limits,  and  even  then  the  forecast  is  not  always  to  be 
trusted.  We  know  from  actual  trial  in  America  that  it  is  possible  to 
drive  a  larger  displacement  and  midship  section  upon  a  decrease  in 
beam  with  no  greater  expenditure  in  power.  This  has  been  suffi- 
ciently confirmed  in  the  comparative  sailing  between  "  cutters  "  and 
"sloops  "  differing  from  one  another  in  the  respects  noted,  and  is  to 
be  traced  to  the  lesser  wave-making  of  the  narrower  form.  Trials 
of  steam  yachts  in  England  have  furthermore  demonstrated  that 
resistance  does  not  vary  as  the  square  of  the  speed,  but  in  a  con- 
stantly growing  ratio  until  high  speed  of  18  knots  has  been  attained, 
when  the  ratio  will  slightly  decline.  It  also  varies  with  the  form  and 
dimensions.  Neither  does  the  I.  H.  P.  vary  as  the  cube  of  the 
speed.  In  the  British  yacht  Mazeppa,  for  example,  the  I.  H.  P. 
from  6  to  8-knot  speed  increased  as  the  square  of  the  speed.  From 
8  to  10  knots  as  the  cube,  and  from  10  to  n^  knots  as  the  4.4 
power.  The  resistance  of  the  same  vessel,  as  measured  by  the 
dynamometer,  grew  directly  as  the  speed  up  to  8  knots,  from  8  to 
10  knots  as  the  square,  and  from  10  to  11^2  nearly  as  the  cube  of  the 
speed. 


io6  The    Screw. 

The  readiest  and  most  reliable  method  of  .apportioning  power  is, 
as  with  the  screw  to  fall  l)ack  upon  experience  and  tentative  pro- 
gression. 

From  the  foregoing  it  will  be  seen  that  every  knot  of  increased 
speed  is  purchased  at  greater  cost  in  power  the  higher  the  speed  of 
the  vessel,  and  that  driving  a  hull  beyond  the  speed  to  which  it  is 
economically  adapted  is  a  wasteful  proceeding. 

It  is  of  course  most  economical  to  steam  at  slow  speeds,  as  the  dis- 
tance covered  per  unit  of  fuel  will  be  greater  than  at  higher  speeds 
with  the  power  required  growing  in  a  faster  ratio  than  the  speed. 

Thus  a  steam  yacht  of  500  tons  displacement,  carrying  100  tons  of 
coal,  upon  trial  was  found  to  burn  2%  tons  per  24  hours  at  8  knots, 
5^  tons  at  10  knots,  and  12^  tons  at  13  knots.  The  coal  at  these 
speeds  would  last  nearly  36,  17  and  8  days,  and  the  distance  covered 
would  be  nearly  7,000,  4,100  and  2,400  miles.  The  economy  per 
mile  is  only  in  the  fuel.  The  longer  time  consumed  in  making  a 
passage  at  low  speed  would  involve  other  expenses  as  to  subsistence, 
wages,  etc.,  which  might  overbalance  the  saving  in  coal. 

More  specific  information  in  further  explanation  of  the  foregoing 
general  review  will  be  found  in  the  following  chapters  detailing 
actual  practice. 


VI. 


U.     S.     LAWS     APPLICABLE     TO     STEAM 

YACHTS. 


THE  exact  status  of  a  steam  yacht  in  the  eyes  of  the  law  has 
long  been  more  or  less  indeterminate,  depending  upon  such 
interpretations  as  were  put  upon  the  U.  S.  Revised  Statutes  by 
successive  Secretaries  of  the  Treasury  and  subordinate  officials. 
Although  legislation  specifically  exempts  steam  as  well  as  sailing 
yachts  from  the  burden  of  Custom  House  entry  and  clearance  and 
from  sundry  taxes  and  dues,  it  has  been  generally  held  that  the 
hull,  equipment  and  machinery  of  a  steam  yacht  are  subject  to  the 
supervision  of  the  Board  of  Supervising  Inspectors  of  Steam  Vessels 
and  their  Rules  and  Regulations  established  in  accordance  with  the 
U.  S.  Statutes. 

It  is  proper  enough  that  the  machinery  of  a  steam  yacht  should 
by  law  be  subjected  to  rigid  inspection  by  disinterested  government 
officers,  both  as  a  guarantee  to  the  owner  as  well  to  the  crew  shipped 
at  his  instigation.  Were  such  supervision  removed,  all  manner  of 
rash  experiments  would  be  indulged  in  with  a  train  of  serious  con- 
sequences, and  unscrupulous  persons  or  over-zealous  inventors  would 
palm  off  upon  the  purchaser  much  worthless  and  dangerous  material. 
There  were  hitherto  some  rules,  which,  though  necessary  and  bene- 


io8         U.  S.  Laws  Applicable  to  Steam  Yachts. 

ficial  to  public  conveyances,  were  vexatious  and  not  applicable  to  the 
proper  and  safe  service  of  a  small  steam  yacht.  Among  these  were 
the  licensing  of  master  and  pilot  and  the  necessity  of  having  such 
officers,  the  numerous  articles  of  outfit  for  fire  and  life  saving  and 
the  cost  of  inspection,  which  in  proportion  to  the  value  of  a  small 
steam  yacht  was  excessive. 

Fortunately,  the  Treasury  Department  and  the  Board  of  Super- 
vising Inspectors  understand  the  situation  well  and  have  always  been 
liberal  in  their  interpretation  of  the  Statutes.  Amendments  have 
been  introduced  and  approved  in  many  of  the  Rules,  extending 
special  privileges  to  yachts  and  vessels  under  one  hundred  tons. 
These  have  in  a  great  measure  relieved  steam  yachting  from  legal 
annoyances. 

By  Act  of  Congress,  approved  June  26,  1886,  all  fees  for  inspection 
of  steamers  and  licensing  of  officers  have  been  abolished.  As  the 
laws  stand  to-day,  the  machinery  and  hull  of  a  yacht  must  be  passed 
upon  annually  by  the  Local  Inspectors  for  the  District.  Engineer, 
pilot  or  master's  "special  license"  will  be  granted  to  any  competent 
person  upon  application  without  payment  of  fee,  but  no  unlicensed 
person  can  undertake  their  duties. 

In  small  yachts  and  launches,  under  one  hundred  tons,  as  near  as 
the  law  is  specific  on  this  point,  no  licensed  "master"  is  required, 
but  engineer  and  pilot  of  the  smallest  launch  must  have  at  least  a 
"special  license."  It  is  well  enough  to  insist  upon  a  license  for  the 
engineer,  but  the  pilot  is  a  superfluous  officer  on  board  of  any  steam 
yacht.  Where  a  licensed  master  is  not  required  by  law,  the  owner 
is  sufficiently  capable  to  act  as  his  own  "pilot,"  and  in  yachts  large 
enough  to  require  a  "licensed  master,"  the  useless  pilot  can  be 
dispensed  with,  for  the  master  can  in  all  cases  also  take  out  a  license 
as  pilot,  if  competent,  thus  combining  the  two  officials  in  one 
person. 

In  1878,  Supervising  Inspector-General  Jas.  A.  Dumont  caused 
the  following  circular  from  the  Treasury  Department  to  be  issued. 
It  covers  the  case  of  steam  launches  under  the  laws  as  they  stand 
this  day,  with  exception  of  the  fee  mentioned  for  "special  engineer" 
license,  which  is  no  longer  imposed. 


U.  S.  Laws  Applicable  to  Steam  Yachts.         109 

No.  2326,  SYNOPSIS  OF  DECISIONS,  1875. 

TREASURY  DEPARTMENT,  July  3,  1875. 

[EXTRACT.] 
*  *  ******* 

Under  Section  4426,  Revised- Statutes,  the  hull  and  boiler  of  every 
yacht,  or  other  small  craft  of  like  character  propelled  by  steam,  must 
be  inspected — the  boiler  being  subjected  to  the  hydrostatic  test  re- 
quired by  law.  The  pilot  and  engineer  must  also  be  licensed;  and 
such  other  provisions  of  the  law  complied  with  as  may  be  applicable 
to  the  particular  vessel  under  examination. 

Sections  4428  and  4431  require  that  the  iron  or  steel  plates  of 
which  the  boiler  is  constructed  must  be  stamped  with  the  name  of 
the  manufacturer,  the  place  where  manufactured,  and  the  number  of 
pounds  tensile  strain  it  will  bear  to  the  sectional  square  inch. 

The  boiler  must  be  provided  with  such  appurtenances  as  are  neces- 
sary to  its  safe  management,  viz:  Feed  pump  and  check  valve,  steam 
pressure  gauge,  safety  valve,  gauge  cocks,  a  water  gauge,  (showing 
the  height  of  the  water  in  the  boiler)  and  blow-off  valve;  and,  if  it  is 
found  applicable  to  the  kind  of  boiler  employed,  a  tin  plug,  so 
inserted  that  it  will  fuse  by  the  heat  of  the  fire  when  the  water  in  the 
boiler  falls  below  the  prescribed  limit. 

There  must  be  on  board  the  means  of  applying  the  required 
hydrostatic  test. 

For  so  small  a  vessel  as  you  describe  .(26  ft.  long)  four  buckets 
kept  on  board  will  be  sufficient  means  for  the  extinguishment  of  fire. 

There  must  be  provided  for  each  person  on  board  a  life  preserver 
containing  at  least  six  pounds  of  good  block  cork,  adjustable  to  the 
body  in  the  manner,  of  a  belt  or  jacket,  with  shoulder  straps. 

The  fee  for  license  as  "special  engineer"  for  this  yacht,  which 
will  be  granted  to  any  person  of  good  character,  who  has  sufficient 
experience  to  manage  the  boiler  and  machinery  safely,  is  five  dollars. 
A  similar  "special  license  "  as  pilot  for  this  vessel  will  be  granted  to 
any  person  of  like  good  character  who  is  familiar  with  the  navigation 
in  which  she  is  to  be  employed,  understands  the  Pilot  Rules,  and  has 
had  sufficient  experience  in  handling  this  or  other  similar  vessels. 


no         U.  S.  Laws  Applicable  to  Steam  Yachts. 

The  master  of  a  vessel  of  this  class  does  not  require  license. 

A  steam  whistle  of  suitable  dimensions  must  be  provided,  with 
which  the  pilot  will  make  the  signals  as  required  by  the  Pilot  Rules 
above  referred  to. 

When   the   equipment   is   completed   and  the  vessel  is  ready  for 
inspection,  it  is  required  that  application  shall  be  made  in  writing  by 
the  master  or  owner  to  the  local  inspectors  within  whose  district  the 
vessel  is  owned  or  employed. 
*  *  ******* 

Very  respectfully, 

[Signed]     CHAS.  F.  CONANT, 

Acting  Secretary. 

The  following  extracts  from  the  Rules  and  Regulations  of  the 
Board  of  Supervising  Inspectors  are  instructive  and  have  special 
interest  to  owners  of  steam  yachts  and  direct  bearing  upon  the  law- 
ful management  of  their  vessels,  after  they  are  in  possession.  These 
"Revised  Statutes"  and  "Rules"  are  in  the  amended  shape  up  to 
January,  1886. 

R.  S.  SEC.  4214.  The  Secretary  of  the  Treasury  may  cause  yachts 
used  and  employed  exclusively  as  pleasure  vessels,  or  designed  as 
models  of  naval  architecture,  if  built  and  owned  in  compliance  with 
the  provisions  of  sections  forty-one  hundred  and  thirty-three  to 
forty-one  hundred  and  thirty-five,  to  be  licensed  on  terms  which  will 
authorize  them  to  proceed  from  port  to  port  of  the  United  States, 
and  by  sea  to  foreign  ports,  without  entering  or  clearing  at  the 
custom  house;  such  license  shall  be  in  such  form  as  the  Secretary  of 
the  Treasury  may  prescribe.  The  owner  of  any  such  vessel,  before 
taking  out  such  license,  shall  give  a  bond  in  such  form  and  for  such 
amount  as  the  Secretary  of  the  Treasury  shall  prescribe,  conditioned 
that  the  vessel  shall  not  engage  in  any  trade,  nor  in  any  way  violate 
the  revenue  laws  of  the  United  States,  and  shall  comply  with  the 
laws  in  all  other  respects.  Such  vessels,  so  enrolled  and  licensed, 
shall  not  be  allowed  to  transport  merchandise  or  carry  passengers 
for  'pay.  Such  vessels  shall  have  their  name  and  port  placed  on  some 
conspicuous  portion  of  their  hulls.  Such  vessels  shall,  in  all  respects, 


U.  S.  Laws  Applicable  to  Steam  Yachts.         1 1 1 

except  as  above,  be  subject  to  the  laws  of  the  United  States,  and 
shall  be  liable  to  seizure  and  forfeiture  for  any  violation  of  the  provi- 
sions of  this  title:  Provided,  That  all  charges  for  license  and  inspec- 
tion fees  for  any  pleasure  vessel  or  yacht  shall  not  exceed  five  dollars, 
and  for  admeasurement  shall  not  exceed  ten  cents  per  ton.  Fees 
abolished,  Act  of  Congress,  June  26,  1886. 

SEC.  4426.  The  hull  and  boilers  of  every  ferry  boat,  canal  boat, 
yacht,  or  other  small  craft  of  like  character,  propelled  by  steam,  shall 
be  inspected  under  the  provisions  of  this  title.  Such  other  provisions 
of  law  for  the  better  security  of  life,  as  may  be  applicable  to  such 
vessels,  shall  by  the  regulations  of  the  board  of  supervising  inspec- 
tors, also  be  required  to  be  complied  with,  before  a  certificate  of 
inspection  shall  be  granted;  and  no  such  vessel  shall  be  navigated 
without  a  licensed  engineer  and  a  licensed  pilot. 

RULE  I.  Every  iron  or  steel  plate  intended  for  the  construction  of 
boilers  to  be  used  on  steam  vessels  shall  be  stamped  by  the  manu- 
facturer in  the  following  manner  :  At  the  diagonal  corners,  at  a 
distance  of  about  four  inches  from  the  edges  and  at  or  near  the 
center  of  the  plate,  with  the  name  of  the  manufacturer,  the  place 
where  manufactured,  and  the  number  of  pounds  tensile  strain  it  will 
bear  to  the  sectional  square  inch. 

RULE  I.  6.  To  ascertain  the  ductility  and  other  lawful  qualities, 
iron  of  45,ooolbs.  tensile  strength,  and  under,  shall  show  a  contrac- 
tion of  area  of  15  per  cent.,  and  each  additional  loolbs.  tensile 
strength  shall  show  one  (i)  per  cent,  additional  contraction  of  area, 
up  to  and  including  55,000  T.  S.  Iron  of  55,000  T.  S.  and  upward, 
showing  twenty-five  (25)  per  cent,  reduction  of  area,  shall  be 
deemed  to  have  the  lawful  ductility.  All  steel  plate  of  one  and  one- 
half  inch  thickness  and  under  shall  show  a  contraction  of  area  of 
not  less  than  fifty  (50)  per  cent.  Steel  plate  over  one-half  inch  in 
thickness  shall  show  a  reduction  of  not  less  than  forty-five  (45)  per 
cent.  Provided,  however,  That  steel  plate  required  for  repairs  to 
boilers  built  previous  to  April  i,  1886,  may  be  used  for  such  repairs 
when  showing  a  contraction  of  area  of  not  less  than  forty  (40)  per 
cent. 


H2         U.  S.  Laws  Applicable  to  Steam  Yachts. 

RULE  II.  3.  The  pressure  for  any  dimension  of  boilers  must  be 
ascertained  by  the  following  rule  :  Multiply  one-sixth  of  the  lowest 
tensile  strength  found  stamped  on  any  plate  in  the  cylindrical  shell 
by  the  thickness,  expressed  in  inches  or  parts  of  an  inch,  of  the 
thinnest  plate  in  the  same  cylindrical  shell,  and  divide  by  the  radius 
or  half  diameter,  also  expressed  in  inches,  and  the  sum  will  be  the 
pressure  allowable  per  square  inch  of  surface  for  single-riveting,  to 
which  add  twenty  per  centum  for  double-riveting. 

RULE  II.  4.  The  hydrostatic  pressure  applied  must  be  in  pro- 
portion of  one  hundred  and  fifty  pounds  to  the  square  inch  to  one 
hundred  pounds  to  the  square  inch  of  the  steam  pressure  allowed 


RULE  II.     9.  Lapwelded  tubes  shall  have  the  following  thickness 

in  inches  : 

Diameter. 

Thickness. 

Diameter. 

Thickness. 

3 

0.109 
O.lOg 

\l 

0.095 
0.083 

2j^ 

0.095 

*/i 

0.072 

2 

0.095 

i 

0.072 

RULE  II.  10.  The  strength  of  corrugated  flues,  when  used  for 
furnaces  or  steam  chimneys,  corrugation  not  less  than  i  y&  in.  deep, 
and  provided  that  the  plain  parts  at  the  ends  do  not  exceed  6  in.  in 
length,  and  the  plates  are  not  less  than  vV  thick,  when  new  corru- 
gated and  practically  true  circles,  to  be  calculated  from  the  follow- 
ing formula: 


12,500 
D 


X  T 


pressure, 


T  being  thickness  in  inches  and  D  the  mean  diameter  in  inches. 

RULE  II.  ii.  The  formulae  for  cylindrical  lapwelded  and 
riveted  flues  in  boilers  to  be  used  as  furnaces,  which  shall  be  used 
in  determining  the  pressure  to  be  allowed  shall  be  as  follows  : 

Let  D  =  diameter  of  flue  in  inches  ;  A  =  89,600,  a  "constant "  ; 
T  =  thickness  of  flue  in  decimals  of  an  inch ;  L  =  length  of  flue 


U.  S.  Laws  Applicable  to  Steam  Yachts.         1 1 3 

in  feet,  not  to  exceed  8  ft. ;    P  =  pressure  of  steam   allowable,  in 

pounds. 

p  =  89.600  X  T8 
L  X  D 

RULE  II.  12.  The  feed  water  shall  not  be  admitted  into  any 
boiler  at  a  temperature  less  than  one  hundred  degrees  Fahrenheit 
for  low-pressure  boilers,  and  one  hundred  and  eighty  for  high- 
pressure  boilers. 

13.  Whenever  steamers  use  a  pressure  upon  their  boilers  exceed- 
ing sixty  pounds  to  the  square  inch,  they  shall  be  inspected  as  high- 
pressure  steamers  and  designated  as  such. 

14.  Vertical  tubular  boilers  shall  not  be  used  on  steamers  navi- 
gating the  Red  River  of  the  North  and  rivers  whose  waters  flow  into 
the  Gulf  of  Mexico,  unless  the  water-line  is  2  in.  above  the  upper 
end  of  the  tubes  and  fire-line. 

1 6.  All  steamers  navigating  the  ocean,  sounds,  lakes,  bays,  and 
rivers,  the  boilers  of  which  shall  be  internally  heated,  shall  have  a 
clear  space  of  at  least  four  inches  on  either  side,  and  at  the  top  not 
less  than  two  inches  clear  space  above  the  covering  of  the  boilers. 

17.  All  boilers  hereafter  placed  in   steamers   shall  have  a  clear 
space  of   at  least  8  in.  between  the  under  side  of  the  cylindrical 
shell  and  the  floor  or  keelson. 

All  man-holes  for  the  shell  of  boilers  shall  have  an  opening  not 
less  in  diameter  than  u  x  15  in.  in  the  clear,  except  that  boilers  less 
than  34  in.  diameter  of  shell  have  an  opening  in  the  clear,  in  man- 
holes of  not  less  than  gx  14^6  in.;  all  boiler  shells  between  34  and 
38  in.  diameter,  an  opening  not  less  than  of  9X16  in.,  and  all  boiler 
shells  between  38  and  48  in.  in  diameter,  an  opening  not  less  than 
nXi5#  in. 

1 8.  All  wood-work   or    other    ignitible    substance,    approaching 
within  2  in.  of  the  boiler,  shall  be  suitably  sheathed  with  metal,  so 
adjusted  as  to  permit  a  free  circulation  of  air  between  the  sheathing 
and  the  ignitible  surface. 

19.  All  boilers  shall  have  a  clear  space  at  the  back  and   ends 
thereof   of  2  ft.   opposite  the   back  connection    door.      Slip    joints 
in  steam-pipes  shall,  in  their  working  parts,  when  the  steamer  is  to 


H4         U.  S.  Laws  Applicable  to  Steam  Yachts. 

be  employed  in  navigating  salt  water,  be  made  of  copper  or  com- 
position. 

20.  There  shall  be  fastened  to  each  boiler  a  plate  containing  the 
name  of  the  manfacturer  of  the  material,  the  place  where  manu- 
factured, the  tensile  strength,  the  name  of  the  builder  of  the  boiler, 
when  and  where  built. 

21.  Every  sea-going  steamer  carrying  passengers  shall  be  supplied 
with  an  auxiliary  or  donkey  boiler  of  sufficient  capacity  to  work  the 
fire-pumps. 

22.  All  steamers  shall  have  inserted  in  their  boilers  plugs  of  Banca 
tin,  at  least  one-half  inch  in  diameter  at  the  smallest  end  of  the 
internal  opening,  in  the  following  manner,  to  wit:  Cylinder  boilers 
with  flues  shall  have  one  plug  inserted  in  one  flue  of  each  boiler;  and 
also  one  plug  inserted  in  the  shell  of  each  boiler  from  the  inside, 
immediately  before  the  fire  line,  and  not  less  than  four  feet  from  the 
forward  end  of  the  boilers.     All  fire-box  boilers  shall  have  one  plug 
inserted  in  the  crown  of  the  back  connection,  or  in  the  highest  fire 
service  of  the  boiler.     All  upright  tubular  boilers  used  for  marine 
purposes  shall  have  a  fusible  plug  inserted  in  one  of  the  tubes  at  a 
point  at  least  two  inches  below  the  lower  gauge  cock,  and  said  plug 
may  be  placed  in  the  upper  head  sheet  when  deemed  advisable  by 
the  local  inspectors.     All  fusible  plugs,  unless  otherwise  provided, 
shall  have  an  external  diameter  not  less  than  that  of  a  one-inch  gas 
or  steam  pipe  screw-tap,  except  when  such  plugs  shall  be  used  in  the 
tubes  of  upright  boilers,  plugs  may  be  used  with  an  external  diameter 
of  not  less  than  that  of  a  three-eighths  of  an  inch  gas  or  steam  pipe 
screw-tap,  said   plugs  to  conform  in  construction  with  plugs  now 
authorized  to  be  used  by  this  board;  and  it  shall  be  the  duty  of  the 
inspectors  to  see  that  these  plugs  are  filled  with  Banca  tin  at  each 
annual  inspection. 

23.  All  steamers  having  one  or  two  boilers  shall  have  three  suit- 
able gauge  cocks  in  each  boiler. 

24.  Lever  safety  valves  to  be  attached  to  marine  boilers  shall  have 
an  area  of .  not  less  than  one  square  inch  to  two  square  feet  of  the 
grate  surface  in  the  boiler,  and  the  seats  of  all  such  safety  valves 


U.  S.  Laws  Applicable  to  Steam  Yachts.         i  T  5 

shall  have  an  angle  of  inclination  of  45  degrees  to  the  center  line  of 
their  axis. 

Any  spring-loaded  safety  valves  constructed  so  as  to  give  an 
increased  lift  by  the  operation  of  steam,  after  being  raised  from  their 
seats,  or  any  spring-loaded  safety  valve  constructed  in  any  other 
mannner  or  so  as  to  give  an  effective  area  equal  to  that  of  the  afore- 
mentioned spring-loaded  safety  valve,  may  be  used  in  lieu  of  the 
common  lever-weighted  valve  on  all  boilers  on  steam  vessels,  and  all 
such  spring-loaded  safety  valves  shall  be  required  to  have  an  area  of 
not  less  than  one  square  inch  to  three  square  feet  of  grate  surface  of 
the  boiler,  and  each  spring-loaded  valve  shall  be  supplied  with  a 
lever  that  will  raise  the  valve  from  its  seat  a  distance  of  not  less  than 
that  equal  to  one-eighth  the  diameter  of  the  valve  opening,  and  the 
seats  of  all  such  safety  valves  shall  have  an  angle  of  inclination  to 
the  center  line  of  their  axis  of  45  degrees.  But  in  no  case  shall  any 
spring-loaded  safety  valve  be  used  in  lieu  of  the  lever-weighted 
safety  valve  without  having  been  approved  by  the  Board  of  Super- 
vising Inspectors. 

Donkey  boilers  used  on  all  steam  vessels  for  driving  pumps,  hoist- 
ing engines,  electric  lights  or  other  purposes  must  be  inspected  the 
same  as  the  main  steam  boilers. 

The  area  of  all  openings  in  boilers  and  connections  leading  from 
boilers  to  safety  valves  shall  not  be  less  than  the  area  of  the  valve 
used. 

26.  All  boilers  or  sets  of  boilers  shall  have  attached  to  them  at 
least  one  gauge  that  will  correctly  indicate  a  pressure  of  steam  equal 
to  eighty  per  cent,  of  the  hydrostatic  pressure  applied  by  the  inspectors. 

28.  There  must  be  means  provided  in  all  boilers  using  the  low 
water  gauges  which  are  operated  by  means  of  a  float  inside  the  same, 
to  prevent  the  float  from  getting  into  the  steam  pipe. 

34.  All  holes  cut  through  the  bottom  or  bilge  of  a  vessel  that  are 
covered  by  a  sea  valve  or  cock  and  secured  to  the  skin  of  the  vessel 
by  bolts  and  connected  to  the  engine  and  boilers  by  pipes,  shall  be 
arranged  so  as  to  be  accessible  at  all  times,  so  that  if  a  leak  or  defect 
occurs  it  can  be  reached.  Valves,  seats,  stems  and  bolts  shall  be  of 
brass  when  used  in  salt  water. 


1 1 6         U.  S.  Laws  Applicable  to  Steam  Yachts. 

A  stop  cock  or  valve  shall  be  placed  between  check  valve  and 
boiler  on  all  feed  pipes  in  order  to  facilitate  access  to  connection. 

RULE  III.  2.  The  carrying  capacity  of  all  lifeboats  shall  be  deter- 
mined by  the  following  rule:  Multiply  length,  breadth  and  depth  to- 
gether and  divide  their  product  by  ten;  the  quotient  will  be  the 
number  of  persons  such  a  boat  is  allowed  to  carry. 

4.  All  lifeboats  must  have,  life-lines  securely  fastened  to  their  gun- 
wales, and  a  good  rope  painter  of  suitable  size  and  length  properly 
attached,  and  every  lifeboat  must  be  supplied  with  not  less  than  four 
oars,  and  kept  in  good  condition  for  immediate  use. 

9.  All  metallic  lifeboats  shall  be  furnished  with  an  automatic  plug. 

10.  One  boat  for  steamers  under  100  tons,  two  boats  from  100  to 
200  tons,  three  boats  from  300  to  400  tons,  five  boats  up  to  500  tons, 
and  six  up  to  1000  tons. 

13.  A  portion  of  lifeboats  may  be  replaced  by  approved  life  rafts. 

14.  All    steamers    navigating    oceans,    northwestern    lakes    and 
sounds,  shall  be  equipped  with  life  rafts  in  proportion  of  one  to  every 
two  lifeboats  required. 

15.  Rubber   and   canvas   rafts  to  be  kept   inflated  at  all  times. 
Granulated  cork  life  rafts  excluded  from  steamers. 

17.  Drags  or  floating  anchors  shall  be  constructed  so  as  to  be 
capable  of  being  compactly  stowed  near  the  head  of  the  ship.  For 
ships  of  400  tons  or  under,  drag  to  have  not  less  than  25  superficial 
feet.  Steamers  whose  routes  do  not  extend  off  anchorage  are  not 
required  to  have  drags  or  floating  anchors  on  board. 

21.  Every  sea- going  steamer  and  every  steamer  navigating  the 
great  northern  and  northwestern  lakes  carrying  passengers  shall  not 
have  less  than  three  watertight  cross  bulkheads.  Such  bulkheads 
shall  reach  to  the  main  deck  in  single  decked  vessels,  otherwise  to 
the  deck  next  below  the  main  deck.  For  wooden  hulls  they  shall  be 
fastened  to  suitable  framework,  which  framework  must  be  securely 
attached  to  the  hull  and  calked.  For  iron  hulls  they  shall  be  well 
secured  to  the  framework  of  the  hulls,  and  strengthened  by  stanchions 
of  angle  iron  placed  not  more  than  two  feet  from  center  to  center. 
One  of  the  bulkheads  must  be  placed  forward  and  one  abaft  of  the 


U.  S.  Laws  Applicable  to  Steam  Yachts.         1 1 7 

engines  and  boilers.  The  third  or  collision  bulkhead  must  be  placed 
not  nearer  than  five  feet  from  the  stem  of  the  vessel.  Iron  bulk- 
heads must  be  made  not  less  than  one-quarter  of  an  inch  in  thickness, 
and  wooden  bulkheads  must  be  of  equal  strength,  and  covered  with 
iron  plates  not  less  than  one-sixteenth  of  an  inch  in  thickness. 

23.  All  open  steam  launches  or  other  steam  vessels  of  five  tons 
burden  or  less,  carrying  passengers,  may  dispense  with  the  lifeboat 
when  such  vessels  are  provided  with  metallic  air  chambers  placed 
under  the  seats  and  in  the  ends  of  said  vessels  of  sufficient  capacity 
to  float  the  inert  weight  of  said  vessel,  including  her  boilers  and 
machinery,  and  such  vessels  shall  also  be  provided  with  one  life 
preserver  for  every  person  which  the  inspection  certificate  shall  allow 
them  to  carry,  including  the  officers  and  crew,  and  every  such  steam 
vessel,  carrying  fifteen  passengers  or  less,  shall  carry  at  least  two  fire 
buckets  and  one  axe. 

RULE  IV.  i.  All  passenger  steamers  are  required  to  be  provided 
with  fire  buckets,  barrels  and  axes  as  follows:  Steamers  not  over  50 
tons,  5  buckets  and  i  axe.  Steamers  not  over  100  tons,  8  buckets 
and  2  axes.  Steamers  not  over  200  tons,  i  barrel,  12  buckets  and  2 
axes.  Steamers  not  over  500  tons,  2  barrels,  15  buckets  and  3  axes. 
Buckets  may  be  substituted  for  barrels.  They  should  be  filled  with 
water. 

8.  All  feed  and  steam  pipes  shall  be  attached  at  their  terminal 
joints,  with  good  and  substantial  flanges.  Double-acting  steam  fire 
pump  for  steamer  under  200  tons  to  have  4  in.  stroke  and  2  in. 
diameter  of  plunger.  For  steamer  under  500  tons,  7  in.  stroke  and 
4  in.  diameter  of  plunger. 

17.  Steam  siphon  pumps  which  have  been  approved  by  the  Board 
of  Supervising  Inspectors  may  be  allowed  in  lieu  of  double-acting 
steam  fire  pumps  on  steamers  under  100  tons. 

RULE  V.  i.  Before  an  "  original  license  "  is  issued  to  any  person 
to  act  as  a  master,  mate,  pilot  or  engineer,  he  must  personally  appear 
before  some  local  board  or  a  supervising  inspector  for  examination; 
but  upon  the  renewal  of  such  license,  when  the  distance  from  any 


1 1 8         U.  S.  Laws  Applicable  to  Steam  Yachts. 

local  board  or  supervising  inspector  is  such  as  to  put  the  person 
holding  the  same  to  great  inconvenience  and  expense  to  appear  in 
person,  he  may,  upon  taking  the  oath  of  office  before  any  person 
authorized  to  adminster  oaths,  and  forwarding  the  same,  together 
with  the  license  to  be  renewed,  to  the  local  board  or  the  supervising 
inspector  of  the  district  in  which  he  resides  or  is  employed,  have  the 
same  renewed  by  the  said  inspectors,  if  no  valid  reason  to  the  con- 
trary be  known  to  them;  and  they  shall  attach  such  oath  to  the  stub 
end  of  the  license,  which  is  to  be  retained  on  file  in  their  office. 

4.  It  shall  be  the  duty  of  an  engineer,  when  he  assumes  charge  of  the 
boilers  and  machinery  of  a  steamer,  to  forthwith  thoroughly  examine 
the  same,  and  if  he  finds  any  part  thereof  in  bad  condition,  caused 
by  neglect  or  inattention  on  the  part  of  his  predecessor,  he  shall  im- 
mediately report  the  facts  to  the  local  inspectors  of  the  district,  who 
shall  thereupon  investigate  the  matter,  and  if  the  former  engineer 
has  been  culpably  derelict  of  duty,  they  shall  suspend  or  revoke  his 
license. 

5.  No  "original  license  "  shall  be  issued  to  any  person  to  act  as  en- 
gineer, except  for  "special  license  "  on  small  pleasure  steamers,  who 
cannot  read  or  write,  or  who  has  not  served  at  least  three  years  in  the 
engineer's  department  of  a  steam  vessel,  or  as  a  regular  machinist  in 
a  machine  works,  provided  that  any  person  who  has  served  for  a 
period  of  three  years  as  a  locomotive  or  a  stationary  engineer  may 
be  licensed  to  act  as  engineer  on  steam  vessels  after  having  not  less 
than  one  year's  experience  in  the  engineer's  department  of  a  steam 
vessel. 

6.  The  navigation  of  every  steamer  above  100  tons  burden  shall 
be  under  the  control  of  a  first-class  pilot,  and  every  such  pilot  shall 
be  limited  in  his  license  to  the  particular  service  for  which  he  is 
adapted.     "  Special  pilots  "  may  also  be  licensed  for  small  steamers 
of  all  kinds,  locally  employed. 

12.  No  original  license  for  any  route  shall  be  issued  to  any  person 
except  for  special  license  on  small  pleasure  steamers  and  ferry  boats 
navigating  outside  of  ports  of  entry  and  delivery,  who  has  not  been 
employed  in  the  deck  department  of  a  steamer  or  sail  vessel  for  the 
term  of  at  least  three  years  preceding  the  application  for  license. 


U.  S.  Laws  Applicable  to  Steam  Yachts.         119 

14.  Whenever  a  master  desires  to  act  as  pilot,  and  furnishes  the 
necessary  evidence  of  his  ability,  the  local  inspectors  for  the  district 
where  the  license  is  issued  shall  indorse  the  route  on  the  master's 
certificate;  and,  in  like  manner,  when  a  first-class  pilot  desires  to  act 
as  mate,  if  the  inspectors  are  satisfied  of  his  ability,  they  shall  indorse 
the  fact  on  the  pilot's  certificate  ;  but  a  mate's  license  cannot  be 
indorsed  as  first  pilot. 

24.  Starting,  stopping  and  backing  signals  for  steam  vessels 
navigating  the  waters  of  the  eighth  and  ninth  supervising  inspection 
districts: 

Eighth  district  embraces  all  the  waters  of  the  lakes  north  and  west 
of  Lake  Erie,  with  their  tributaries,  and  the  upper  portion  of  the 
Illinois  River  down  to  and  including  Peoria,  111. 

Ninth  district  embraces  all  the  waters  of  Lakes  Erie,  Ontario, 
Champlain,  Memphremagog,  and  the  river  St.  Lawrence,  and  their 
tributaries. 

There  shall  be  used  between  the  master  or  pilot  and  engineer  the 
following  code  of  signals,  to  be  made  by  bell  or  whistle,  namely: 

i  whistle  or  bell    • Go  ahead. 

1  whistle  or  bell Stop. 

2  whistles  or  bells NBack. 

3  whistles  or  bells Check. 

i  long  whistle  or  4  bells Strong. 

i  long  whistle  or  4  bells All  right. 

Two  whistles  or  2  bells,  when  the  engine  is  working  ahead,  will 
always  be  a  signal  to  stop  and  back  strong. 

Masters  and  pilots  of  steamers  on  lakes  and  seaboard  are  required 
to  have  their  wheel  chains  rove  so  that  the  wheel  and  helm  shall 
move  in  the  same  direction,  so  that  when  the  wheel  is  put  to  star- 
board the  vessel's  head  shall  go  to  port,  and  when  the  wheel  is  put 
to  port  the  vessel's  head  shall  go  to  the  starboard. 

RULE  VI.  i.  The  annual  inspection  of  a  steamer  must  be  made 
only  on  written  application  presented  to  the  United  States  inspectors 


1 20         U.  S.  Laws  Applicable  to  Steam  Yachts. 

by  the   owner,  master   or   authorized   agent  of  the  steamer  to  be 
inspected. 

4.  In  the  inspection  of  the  hull  of  steamers,  if  the  inspector  shall 
not  have  satisfactory  evidence  otherwise  of  the  soundness  of  the 
timber,  he  shall  not  give  a  certificate  until  the  hull  of  the  vessel  shall 
be  bored  to  his  satisfaction. 

RULE  IX.  14.  When  it  is  known,  or  comes  to  the  knowledge  of 
the  local  inspectors,  that  any  steam  vessel  is  or  has  been  carrying  an 
excess  of  steam  beyond  that  which  is  allowed  by  her  certificate  of 
inspection,  it  is  recommended  that  the  local  inspectors  in  whose 
district  said  steamer  is  being  navigated,  in  addition  to  reporting  the 
fact  to  the  United  States  District  Attorney  for  prosecution  under 
Section  4437,  Revised  Statutes,  shall  require  the  owner  or  owners  of 
said  steamer  to  place  on  the  boiler  of  said  steamer  a  lock-up  safety 
valve  that  will  prevent  the  carrying  of  an  excess  of  steam,  and  shall 
be  under  the  control  of  said  local  inspectors. 

On  the  placing  of  a  lock-up  safety  valve  upon  any  boiler,  it  shall 
be  the  duty  of  the  engineer  in  charge  of  same  to  blow,  or  cause  the 
said  valve  to  blow  off  steam  at  least  once  in  each  watch  of  six  hours 
or  less,  to  determine  whether  the  valve  is  in  working  order,  and  it 
shall  be  his  duty  to  report  to  the  local  inspectors  any  failure  of  such 
valve  to  operate. 

In  case  no  such  report  is  made,  and  a  safety  valve  is  found  that 
has  been  tampered  with,  or  out  of  order,  the  license  of  the  engineer 
having  such  boiler  in  charge  shall  be  revoked. 

RULE  X.  2.  All  the  equipments  of  a  steamer,  such  as  buckets, 
axes,  boats,  oars,  rafts,  shall  be  painted  or  branded  with  the  name 
of  the  steamer  to  which  they  belong. 

3.  No  oil  that  will  stand  a  fire-test  of  less  than  300  deg.  Fahren- 
heit shall  be  used  as  stores  on  any  steamer  carrying  passengers. 

6.  All  steamers  navigating  rivers,  lakes,  bays  and  sounds  in  the 
night  time,  shall  have  one  watchman  at  the  bow. 


U.  S.  Laws  Applicable  to  Steam  Yachts.         1 2 1 


PILOT    RULES    FOR    LAKE    AND    SEABOARD. 

RULE  I.  When  steamers  are  approaching  each  other  "head  and 
head,"  or  nearly  so,  it  shall  be  the  duty  of  each  steamer  to  pass  to 
the  right,  or  port  side  of  the  other  ;  and  the  pilot  of  either  steamer 
may  be  first  in  determining  to  pursue  this  course,  and  thereupon 
shall  give,  as  a  signal  of  his  intention,  one  short  and  distinct  blast  of 
his  steam-whistle,  which  the  pilot  of  the  other  steamer  shall  answer 
promptly  by  a  similar  blast  of  his  steam-whistle,  thereupon  such 
steamers  shall  pass  to  the  right,  or  port  side  of  each  other.  But  if 
the  course  of  such  steamers  is  so  far  on  the  starboard  of  each  other 
as  not  to  be  considered  by  pilots  as  meeting  "head  and  head,"  or 
nearly  so,  the  pilot  so  first  deciding  shall  immediately  give  two  short 
and  distinct  blasts  of  his  steam-whistle,  which  the  pilot  of  the  other 
steamer  shall  answer  promptly  by  two  similar  blasts  of  his  steam- 
whistle,  and  they  shall  pass  to  the  left,  or  on  the  starboard  side,  of 
each  other. 

NOTE. — In  the  night,  steamers  will  be  considered  as  meeting  "head  and  head" 
so  long  as  both  the  colored  lights  of  each  are  in  view  of  the  other. 

RULE  II.  When  steamers  are  approaching  each  other  in  an 
oblique  direction  they  shall  pass  to  the  right  of  each  other,  as  if 
meeting  "head  and  head,"  or  nearly  so,  and  the  signals  by  whistle 
shall  be  given  and  answered  promptly  as  in  that  case  specified. 

RULE  III.  If,  when  steamers  are  approaching  each  other,  the 
pilot  of  either  vessel  fails  to  understand  the  course  or  intention  of 
the  other,  whether  from  signals  being  given  or  answered  erroneously, 
or  from  other  causes,  the  pilot  so  in  doubt  shall  immediately  signify 
the  same  by  giving  several  short  and  rapid  blasts  of  the  steam- 
whistle  ;  and  if  the  vessels  shall  have  approached  within  half  a  mile 
of  each  other,  both  shall  be  immediately  slowred  to  a  speed  barely 
sufficient  for  steerage-way  until  the  proper  signals  are  given, 
answered,  and  understood,  or  until  the  vessels  shall  have  passed 
each  other. 


122         U.  S.  Laws  Applicable  to  Steam  Yachts. 

RULE  IV.  When  steamers  are  running  in  a  fog  or  thick  weather, 
it  shall  be  the  duty  of  the  pilot  to  cause  a  long  blast  of  the  steam- 
whistle  to  be  sounded  at  intervals  not  exceeding  one  minute. 

Steamers,  when  DRIFTING  or  at  ANCHOR,  in  the  fair-way  of  other 
vessels  in  a  fog  or  thick  weather,,  shall  ring  their  bells  at  intervals  of 
not  more  than  two  minutes. 

RULE  V.  Whenever  a  steamer  is  nearing  a  short  bend  or  curve 
in  the  channel,  where,  from  the  height  of  the  banks  or  other  cause, 
a  steamer  approaching  from  the  opposite  direction  cannot  be  seen 
for  a  distance  of  half  a  mile,  the  pilot  of  such  steamer,  when  he 
shall  have  arrived  within  half  a  mile  of  such  curve  or  bend,  shall 
give  a  signal  by  one  long  blast  of  the  steam-whistle,  which  signal 
shall  be  answered  by  a  similar  blast,  given  by  the  pilot  of  any 
approaching  steamer  that  may  be  within  hearing.  Should  such 
signal  be  so  answered  by  a  steamer  upon  the  further  side  of  such 
bend,  then  the  usual  signals  for  meeting  and  passing  shall  imme- 
diately be  given  and  answered  ;  but  if  the  first  alarm  signal  of  such 
pilot  be  not  answered,  he  is  to  consider  the  channel  clear  and  govern 
himself  accordingly. 

RULE  VI.  The  signals,  by  the  blowing  of  the  steam-whistle,  shall 
be  given  and  answered  by  pilots,  in  compliance  with  these  rules,  not 
only  when  meeting  "head  and  head,"  or  nearly  so,  but  at  all  times 
when  passing  or  meeting  at  a  distance  within  half  a  mile  of  each 
other,  and  whether  passing  to  the  starboard  or  port. 

RULE  VII.  When  two  steamers  are  approaching  the  narrows 
known  as  "Hell  Gate,"  on  the  East  River,  at  New  York,  side  by 
side,  or  nearly  so,  running  in  the  same  direction,  the  steamer  on  the 
right  or  starboard  hand  of  the  other  (when  approaching  from  the 
west),  when  they  shall  have  arrived  abreast  of  the  north  end  of 
Blackwell's  Island,  shall  have  the  right  of  way,  and  the  steamer  on 
the  left  or  port  side  shall  check  her  way  and  drop  astern.  In  like 
case  when  two  steamers  are  approaching  from  the  east,  and  are 
abreast  at  Negro  Point,  the  steamer  on  the  right  or  starboard  hand 
of  the  other  shall  have  the  right  of  way,  and  shall  proceed  on  her 


U.  S.  Laws  Applicable  to  Steam  Yachts.         123 

course  without  interference,  and  the  steamer  on  the  port  side  of  the 
other  shall  keep  at  a  safe  distance  astern  (not  less  than  three 
lengths)  until  both  steamers  have  passed  through  the  difficult 
channel. 

RULE  VIII.  When  steamers  are  running  in  the  same  direction, 
and  the  pilot  of  the  steamer  which  is  astern  shall  desire  to  pass  on 
the  right  or  starboard  hand  of  the  steamer  ahead,  he  shall  give  one 
short  blast  of  the  steam-whistle  as  a  signal  of  such  desire  and  inten- 
tion, and  shall  put  his  helm  to  port ;  and  the  pilot  of  the  steamer 
ahead  shall  answer  by  the  same  signal,  or,  if  he  prefer  to  keep  on 
his  course,  he  shall  give  two  short  and  distinct  blasts  of  the  steam- 
whistle,  and  the  boat  wishing  to  pass  must  govern  herself  accord- 
ingly, but  the  boat  ahead  shall  .in  no  case  attempt  to  cross  her  bow 
or  crowd  upon  her  course. 

N.  B. — The  foregoing  rules  are  to  be  complied  with  in  all  cases  except  when 
steamers  are  navigating  in  a  crowded  channel,  or  in  the  vicinity  of  wharves;  under 
such  circumstances  steamers  must  be  run  and  managed  with  great  caution,  sound- 
ing the  whistle,  as  may  be  necessary  to  guard  against  collision  or  other  accidents. 

SEC.  4233,  REVISED  STATUTES. — RULE  XXIV.  In  construing  and  obeying 
these  rules,  due  regard  must  be  had  to  all  dangers  of  navigation,  and  to  any  special 
circumstances  which  may  exist  in  any  particular  case  rendering  a  departure  from 
them  necessary  in  order  to  avoid  immediate  danger. 

The  line  dividing  jurisdiction  between  Pilot  Rules  on  Western 
Rivers  and  Lakes  and  Seaboard  at  New  Orleans  shall  be  the  lower 
limits  of  the  city. 

PILOT    RULES    FOR    WESTERN    RIVERS. 

RULE  I.  When  steamers  are  approaching  each  other  from 
opposite  directions,  the  signals  for  passing  shall  be  one  blast  of 
the  steam-whistle  to  pass  to  the  right,  and  two  blasts  of  the  steam- 
whistle  to  pass  to  the  left.  The  pilot  on  the  ascending  steamer 
shall  be  the  first  to  indicate  the  side  on  which  he  desires  to  pass ; 
but  if  the  pilot  of  the  descending  steamer  shall  deem  it  dangerous 
to  take  the  side  indicated  by  the  pilot  of  the  ascending  steamer,  he 


12  4         U.  S.  Laws  Applicable  to  Steam  Yachts. 

shall  at  once  indicate  with  his  steam-whistle  the  side  on  which  he 
desires  to  pass,  and  the  pilot  on  the  ascending  steamer  shall  govern 
himself  accordingly,  the  descending  steamer  being  deemed  to  have 
the  right  of  way.  But  in  no  case  shall  pilots  on  steamers  attempt 
to  pass  each  other  until  there  has  been  a  thorough  understanding 
as  to  the  side  each  steamer  shall  take.  The  signals  for  passing 
must  be  made,  answered,  and  understood  before  the  steamers  have 
arrived  at  a  distance  of  800  yds.  of  each  other. 

RULE  II.  If  from  any  cause  the  signals  for  passing  are  not  made 
at  the  proper  time,  as  provided  in  Rule  /.,  or  should  the  signals  be 
given  and  not  properly  understood,  from  any  cause  whatever,  and 
either  boat  become  imperiled  thereby,  the  pilot  on  either  steamer 
may  be  the  first  to  sound  the  alarm  or  danger  signal,  which  shall 
consist  of  three  or  more  short  blasts  of  the  steam-whistle  in  quick 
succession.  Whenever  the  danger  signal  is  given  the  engines  of 
both  steamers  must  be  stopped  and  backed  until  their  headway  has 
been  fully  checked,  nor  shall  the  engines  of  either  steamer  be  again 
started  ahead  until  the  steamers  can  safely  pass  each  other. 

RULE  III.  When  two  boats  are  about  to  enter  a  narrow  channel 
at  the  same  time,  the  ascending  boat  shall  be  stopped  below  such 
channel  until  the  descending  boat  shall  have  passed  through  it ;  but 
should  two  boats  unavoidably  meet  in  such  channel,  then  it  shall  be 
the  duty  of  the  pilot  of  the  ascending  boat  to  make  the  proper 
signals,  and  when  answered,  the  ascending  boat  shall  lie  as  close  as 
possible  to  the  side  of  the  channel  the  exchange  of  signals  may  have 
determined,  as  provided  by  Rule  I.,  and  either  stop  the  engines  or 
move  them  so  as  only  to  give  the  boat  steerage-way,  and  the  pilot  of 
the  descending  boat  shall  cause  his  boat  to  be  worked  slowly  until 
he  has  passed  the  ascending  boat. 

RULE  IV.  When  a  steamer  is  ascending  and  running  close  on  a 
bar  or  shore,  the  pilot  shall  in  no  case  attempt  to  cross  the  river 
when  a  descending  boat  shall  be  so  near  that  it  would  be  possible 
for  a  collision  to  ensue  therefrom. 


U.  S.  Laws  Applicable  to  Steam  Yachts.         125 

RULE  V.  When  any  steamer,  whether  ascending  or  descending, 
is  nearing  a  short  bend  or  point,  where  from  any  cause,  a  steamer 
approaching  in  an  opposite  direction  cannot  be  seen  at  a  distance  of 
600  yards,  the  pilot  of  such  steamer,  when  he  shall  have  arrived 
within  600  yards  of  that  bend  or  point,  shall  give  a  signal  of  one 
long  sound  of  his  steam-whistle,  as  a  notice  to  any  steamer  that  may 
be  approaching ;  and  should  there  be  any  approaching  steamer  within 
hearing  of  such  signal,  it  shall  be  the  duty  of  the  pilot  thereof  to 
answer  such  signal  by  one  long  sound  of  his  steam-whistle,  when 
both  boats  shall  be  navigated  with  the  proper  precautions,  as  re- 
quired by  preceding  rules. 

RULE  VI.  When  a  steamer  is  running  in  a  fog  or  thick  weather, 
it  shall  be  the  duty  of  the  pilot  to  souud  his  steam-whistle  at  intervals 
not  exceeding  one  minute. 

RULE  VII.  When  steamers  are  running  in  the  same  direction, 
and  the  pilot  of  the  boat  astern  shall  desire  to  pass  either  side  of  the 
boat  ahead,  he  shall  give  the  signal,  as  in  Rule  I.,  and  the  pilot  of 
the  boat  ahead  shall  answer  by  the  same  signal,  or  if  he  prefer  to 
keep  on  his  course,  he  shall  make  the  necessary  signals,  and  the 
boat  wishing  to  pass  must  govern  herself  accordingly;  but  the  boat 
ahead  shall  in  no  case  attempt  to  cross  her  bow  or  crowd  upon  her 
course. 

RULE  VIII.  When  boats  are  moving  from  their  docks  or  berths, 
and  other  boats  are  liable  to  pass  from  any  direction  toward  them, 
they  shall  give  the  same  signal  as  in  case  of  boats  meeting  at  abend; 
but  immediately  after  clearing  the  berths  so  as  to  be  fully  in  sight 
they  shall  be  governed  by  Rule  I. 

RULE  IX.  All  barges  in  tow  of  steamers  between  sunset  and 
sunrise  shall  have  their  signal  lights,  as  required  by  law,  placed  in  a 
suitable  manner  on  the  starboard  bow  of  the  starboard  barge,  and 
on  port  bow  of  the  port  barge,  which  lights  shall  not  be  less  than 
10  ft.  above  the  surface  of  the  water. 


126         U.  S.  Laws  Applicable  to  Steam  Yachts. 


LIGHTS  FOR  STEAM  VESSELS. 

STEAM  AND  SAIL  VESSELS. 

R.  S.  SEC.  4233. — RULE  I.  Every  steam  vessel  which  is  under 
sail  and  not  under  steam  shall  be  considered  a  sail  vessel;  and  every 
steam  vessel  which  is  under  steam,  whether  under  sail  or  not,  shall 
be  considered  a  steam  vessel. 

LIGHTS. 

RULE  II.  The  lights  mentioned  in  the  following  rules,  and  no 
others,  shall  be  carried  in  all  weather,  between  sunset  and  sunrise: 

RULE  III.  All  ocean-going  steamers  and  steamers  carrying  sail, 
shall,  when  under  way,  carry: 

(A)  At  the  foremasthead,  a  bright  white  light,  of  such  a  character 
as  to  be  visible  on  a  dark  night,  with  a  clear  atmosphere,  at  a  dis- 
tance of  at  least  five  miles,  and  so  constructed  as  to  show  a  uniform 
and  unbroken  light  over  an  arc  of  the  horizon  of  twenty  points  of 
the  compass,  and  so  fixed  as  to  throw  the  light  ten  points  on  each 
side  of  the  vessel,  namely,  from  right  ahead  to  two  points  abaft  the 
beam  on  either  side. 

(B)  On  the  starboard  side,  a  green  light,  of  such  a  character  as 
to  be  visible  on  a  dark  night,  with  a  clear  atmosphere,  at  a  distance 
of  at  least  two  miles,  and  so  constructed  as  to  show  a  uniform  and 
unbroken  light   over  an  arc  of  the   horizon  of  ten  points  of  the 
compass,  and  so  fixed  as  to  throw  the  light  from  right  ahead  to  two 
points  abaft  the  beam  on  the  starboard  side. 

(C)  On  the  port  side,  a  red  light,  of  such  a  character  as  to  be 
visible  on  a  dark  night,  with  a  clear  atmosphere,  at  a  distance  of  at 
least   two   miles,  and   so   constructed   as   to   show   a   uniform   and 
unbroken  light  over  an  arc  of  the  horizon  of  ten   points   of  the 
compass,  and  so  fixed  as  to  throw  the  light  from  right  ahead  to  two 
points  abaft  the  beam  on  the  port  side. 

The  green  and  red  lights  shall  be  fitted  with  inboard  screens,  pro- 
jecting at  least  three  feet  forward  from  the  lights,  so  as  to  prevent 
them  from  being  seen  across  the  bow. 


U.  S.  Laws  Applicable  to  Steam  Yachts.         127 

RULE  IV.  Steam  vessels,  when  towing  other  vessels,  shall  carry 
two  bright  white  masthead  lights  vertically,  in  addition  to  their  side 
lights,  so  as  to  distinguish  them  from  other  steam  vessels.  Each  of 
these  masthead  lights  shall  be  of  the  same  character  and  construction 
as  the  masthead  lights  prescribed  by  Rule  III. 

RULE  V.  All  steam  vessels,  other  than  ocean-going  steamers,  and 
steamers  carrying  sail,  shall,  when  under  way,  carry  on  the  starboard 
and  ports  sides  lights  of  the  same  character  and  construction  and  in 
the  same  position  as  are  prescribed  for  side  lights  by  Rule  III., 
except  in  the  case  provided  in  Rule  VI. 

RULE  VI.  River  steamers  navigating  waters  flowing  into  the 
Gulf  of  Mexico  and  their  tributaries  shall  carry  the  following  lights, 
namely:  One  red  light  on  the  outboard  side  of  the  port  smokepipe, 
and  one  green  light  on  the  outboard  side  of  the  starboard  smoke- 
pipe.  Such  lights  shall  show  both  forward  and  abeam  on  their 
respective  sides. 

RULE  VII.  All  coasting  steam  vessels,  and  steam  vessels  other 
than  ferry  boats  and  vessels  otherwise  expressly  provided  for, 
navigating  the  bays,  lakes,  rivers  or  other  inland  waters  of  the  United 
States,  except  those  mentioned  in  Rule  VI.,  shall  carry  the  red  and 
green  lights,  as  prescribed  for  ocean-going  steamers;  and,  in  addition 
thereto,  a  central  range  of  two  white  lights;  the  after  light  being 
carried  at  an  elevation  of  at  least  fifteen  feet  above  the  light  at  the 
head  of  the  vessel.  The  head  light  shall  be  so  constructed  as  to 
show  a  good  light  through  twenty  points  of  the  compass,  namely: 
From  right  ahead  to  two  points  abaft  the  beam  on  either  side  of  the 
vessel;  and  the  after  light  so  as  to  show  all  around  the  horizon.  The 
lights  for  ferryboats  shall  be  regulated  by  such  rules  as  the  Board  of 
Supervising  Inspectors  of  Steam  Vessels  shall  prescribe. 

A  bright  white  light,  not  exceeding  twenty  feet  above  the  hull, 
shall  be  exhibited  by  all  steamers  when  at  anchor  between  sunset  and 
sunrise,  in  a  globular  lantern  of  eight  inches  in  diameter,  so  placed 
as  to  throw  a  good  light  all  around  the  horizon. 

Sailing  vessels  shall  at  all  times,  on  the  approach  of  any  steamer 


128         U.  S.  Laws  Applicable  to  Steam  Yachts. 

during  the  night  time,  show  a  lighted  torch  upon  that  point  or 
quarter  to  which  such  steamers  shall  be  approaching.  And  upon 
any  craft  navigating  rivers  without  being  in  tow  of  a  steamer,  such 
as  rafts,  flatboats,  wood  boats,  and  other  like  craft,  they  shall  sound 
a  fog  horn  at  intervals  of  not  more  than  two  minutes. 

It  shall  at  all  times  be  the  duty  of  steamers  to  give  to  the  sailing 
vessel,  or  other  craft  propelled  by  sails,  every  advantage,  and  keep 
out  of  her  way. 


In  the  case  of  the  steam  yacht  Yosemite  vs.  the  river  steamboat 
Vanderbilt,  the  Court  of  Appeals  decided  in  March,  1887,  that  steam 
yachts  must  show  the  light  prescribed  for  coasting  steamers  under 
Rule  VII. 


VII. 
EXTRACTS  FROM  LLOYD'S  RULES. 

CONCERNING    STEAM    YACHTS. 

SEC.  6.  Stern  and  propeller  posts  and  after  end  of  keel  for  single 
screw  yachts  must  be  double  the  sectional  area  prescribed  for 
keels  in  the  tables  of  the  Yacht  Register,  and  the  keel  tapered  fair  to  it. 

The  portion  of  the  forging  of  the  stern  frame,  forming  part  of  the 
keel,  is  to  extend  sufficiently  forward  for  the  after  end  of  the  scarph 
in  paddle  steamers  to  be  at  least  once  and  a  half  the  frame  space 
before  the  sternpost ;  and  in  screw-propelled  vessels  at  least  twice 
and  a  half  the  frame  space  before  the  propeller  post.  The  rudder 
braces  to  be  forged  on  to  the  sternpost. 

9.  Steam  vessels  to  have  double  reversed  angle  irons  on  floor 
under  engines  and  boilers. 

17.  The  garboard  strakes  of  screw-propelled  yachts,  if  seven- 
sixteenths  of  an  inch,  or  more,  in  thickness,  may  be  reduced  one- 
sixteenth  of  an  inch  before  the  half-length  only.  Paddle  steamers 
may  also  reduce  the  thickness  abaft  the  half-length  of  the  vessel. 
Boss  plates  covering  the  screw-shaft  are  to  be  of  the  same  thickness 
as  the  strakes  amidships  of  which  they  form  part. 

21.  Steam  vessels,  where  the  number  is  1500  and  above,  are  to 
have  iron  watertight  engine  and  boiler  room  bulkheads,  and  the  space 
around  the  stern  tube  must  be  inclosed  in  an  iron  watertight  com- 
partment, and  all  vessels,  when  the  number  is  7000  and  above,  are  to 
have  an  iron  watertight  bulkhead  fitted  forward.  [These  "numbers" 


1 30  Extracts  from  Lloyd's  Rules. 

are  obtained  by  adding  half  the  breadth  of  the  vessel  amidships,  the 
depth  from  top  of  keel  to  underside  of  upper  deck  beams  and  the 
girth  of  the  half  midship  frame.  The  sum  will  give  the  "  number  " 
for  regulating  sizes  of  frames,  reversed  frames,  floors  and  bulkheads. 
When  multiplied  by  the  length  of  the  vessel,  it  will  give  the  "  num- 
ber" for  regulating  sizes  of  keel,  stem,  post,  keelson,  stringer  plates, 
side  plating,  deck  tie  plates  and  rudder.] 

Watertight  bulkheads  must  be  fitted  with  sluice  valves  and  cocks. 
to  allow  the  bilge  water  to  reach  the  pumps,  and  the  valves  must  be 
controlled  from  above  the  waterline. 

24.  Skylights  to  engine  rooms  are  in  all  cases  to  be  substantially 
constructed;  the  coaming  to  which  they  are  attached  should  be  of 
iron,  efficiently  fastened  to  the  beams.  Skylights  to  be  securely 
attached  to  the  coamings  and  the  glass  in  them  should  be  protected, 
and  in  addition,  deadlights  must  be  fitted  and  arrangements  made 
for  their  efficient  security  in  bad  weather. 

26.  Engine  and  boiler  bearers  must  be  properly  constructed,  and 
the  engine  seatings  efficiently  secured  to  them. 

In  vessels  where  the  "number  "  is  3500  and  above,  double  reversed 
angle  irons  must  be  fitted  across  the  vessel  to  every  floor  under 
engines  and  boilers,  and  under  the  boilers  the  floor  plates  must  be 
increased  one-sixteenth  of  an  inch  in  thickness. 

27.  Coal  bunker  openings  are  to  be  fitted  with  gratings  and  lids, 
and  the  lids  must  be  secured  with  approved  fastenings. 

35.  In  cases  where  it  is  proposed  to  construct  boilers  of  steel  for 
classed  vessels  or  vessels  intended  for  classification,  the  material  is 
required  to  fulfil  the  following  conditions: 

The  material  is  to  have  an  ultimate  tensile  strength  of  not  less 
than  26  and  not  more  than  30  tons  per  square  inch  of  section,  with 
an  ultimate  elongation  of  not  less  than  20  per  cent,  in  a  length  of 
Sin.  It  is  to  be  capable  of  being  bent  to  a  curve  of  which  the  inner 
radius  is  not  greater  than  one-and-a-half  times  the  thickness  of  the 
plates  or  bars,  after  having  been  heated  uniformly  to  a  low  cherry 
red  and  quenched  in  water  of  82  deg.  Fahrenheit. 

Steel  rivets  are  to  be  considered  as  part  of  the  material,  and  in 
addition  to  being  subjected  to  a  shearing  test,  they  must  be  capable 


Extracts  from  Lloyd's  Rules.  131 

of  withstanding  the  same  tests  as  the  plates  are  required  to  undergo. 

All  the  holes  in  steel  boilers  should  be  drilled,  but  if  they  be 
punched  the  plates  are  to  be  afterward  annealed. 

All  plates  that  are  dished  or  flanged  are  to  be  annealed  after  the 
operations  are  completed. 

No  steel  stays  are  to  be  welded. 

Boilers  to  be  tested  to  twice  their  working  pressure. 

Two  safety  valves  to  be  fitted  to  each  boiler,  with  combined  areas 
at  least  half  a  square  inch  to  each  square  foot  of  grate  surface. 
Approved  safety  valve  also  to  be  fitted  to  the  superheater. 

Stop  valves  so  that  each  boiler  can  be  worked  separately.  Steam 
gauge  to  each  boiler.  Also  blow-off  cock  independent  of  that  on 
the  vessel's  outside  plating. 

Engines  to  have  two  feed  pumps  and  two  bilge  pumps  if  over  70 
H.  P.  Bilge  injection  must  also  be  fitted  to  the  circulating  pump. 

A  donkey  pump  is  to  be  provided  for  supplying  boilers  with  water, 
taking  it  also  from  each  compartment.  If  no  hand  pump  is  fitted, 
the  donkey  pump  must  be  fitted  to  work  by  hand  also. 

Steam  and  feed  pipes  to  be  of  copper. 

Pipes  through  the  bunkers  to  be  protected. 

Bilge  suction  to  pump  from  each  compartment. 

Sea  cocks  to  be  above  engine  room  platform.  Gun  metal  rings 
around  blow-offs. 

The  strength  of  circular  shells  to  be  calculated  from  the  strength 
of  the  longitudinal  joints  by  the  following  formula: 

C  V  T  V  B 

_  =  working  pressure. 

C  =  coefficient,  as  per  table  following.  T  =  thickness  of  plates 
in  inches.  D  =  mean  diameter  of  shell  in  inches.  B  =  percentage 
of  strength  of  joint  found  as  follows,  the  least  percentage  to  be 

taken  : 

p  —  d 
For  plate  at  joint,  B  =  — - —  X  100. 

For  rivets  at  joint,  B  =  *  *^!  x  100  with  punched  holes, 
Or,  B  =  "      J?   X  90  with  drilled  holes. 


132 


Extracts  from  Lloyd's  Rules. 


In  case  of  rivets  being  in  double  sheer,  1.75  a  is  to  be  used  instead 
of  a.  In  these  formulae,  /  =  pitch  of  rivets  ;  d  =  diameter  of 
rivets ;  a  =  sectional  area  of  rivets ;  n  =  number  of  rows  of  rivets. 


TABLE   OF  COEFFICIENTS  FOR  IRON  BOILERS. 


• 

For  Y2  in.  thick- 
ness and  under. 

For  Y2  to  y±  in. 

Over  2£in. 

Lap  joints    punched  holes 

jee 

16^ 

I7O 

Lap  joints    drilled  holes       

1  7O 

1  80 

IQO 

Double  butt  strap,  punched  
Double  butt  strap     drilled 

170 

1  80 

1  80 
IQO 

I90 
2OO 

TABLE   OF   COEFFICIENTS   FOR  STEEL  BOILERS. 


$i  in.  plates  or 
less. 

%  to  -,a6-in. 

Over  -ja6  in. 

Lap  joints  

2OO 

2IC 

2^0 

Double  butt  strap  joints. 

2JC 

2ao 

2co 

For  all  shell  plates  of  superheaters  or  steam  chests,  the  coefficient 
should  be  two-thirds  the  above.  All  manholes  to  be  stiffened  with 
compensating  rings.  Shell  plates  under  domes  in  boilers  so  fitted, 
to  be  stayed  from  top  of  dome  or  stiffened. 

Stays  supporting  the  flat  surfaces  are  not  to  be  subjected  to  a 
greater  strain  than  6,000  Ibs.  per  sq.  in.  of  section,  or  8,000  Ibs.  if  of 
steel,  calculated  from  weakest  part  of  the  stay  or  fastening.  No 
steel  stays  are  to  be  welded. 

The  strength  of  flat  plates  supported  by  stays  to  be  taken  from 
the  following  formula  : 

C  x  T2 

=  working  pressure  in  pounds  per  square  inch. 

p2 

Where  T  =  thickness  of  plate  in  sixteenths  of  an  inch;  P  =  great- 
est pitch  in  inches;  C  =  90  for  plates  ~h  thick  and  below,  fitted  with 
screw  stays  and  riveted  heads;  C  =  100  for  plates  above  -fr;  C  =  1 10 


Extracts  from  Lloyd" s  Rules.  133 

for  plates  -fe  thick  and  under,  fitted  with  screw  stays  and  nuts  ; 
C  =  120  for  plates  above  A  thick  ;  C  =  140  for  plates  fitted  with 
screw  stays  and  double  nuts  ;  C  =  160  for  plates  fitted  with  stays 
with  double  nuts  and  washers  at  least  half  thickness  of  plates  and  a 
diameter  of  I  of  the  pitch,  riveted  to  the  plates. 

In  case  of  front  plate  of  boilers  in  the  steam  space,  these  numbers 
should  be  reduced  20  per  cent.,  unless  plates  are  guarded  from  direct 
influence  of  the  heat. 

The  strength  of  girders  supporting  the  tops  of  combustion 
chamber  and  other  flat  surfaces,  to  be  taken  from  the  following 
formula : 

C  X  d*  X  T 

=  working  pressure  in  pounds  per  square  inch. 

(L— P)  XDXL 

Where  L  =  length  of  the  girder  in  inches;  P  =  pitch  of  the  stays; 
D  =  distance  apart  of  the  girders;  d  =  depth  of  girder  at  center; 
T  =  thickness  of  girder  at  center  ;  C  =  6,000  if  there  is  one  stay 
to  each  girder,  9,000  if  there  are  two  or  three  stays,  10,200  if  there 
are  four  stays. 

The  strength  of  furnaces  to  resist  collapsing  to  be  calculated  from 
the  following  formula : 

89,600  x  T2 

=  working  pressure  in  pounds  per  square  inch. 

L  X  D 

Where  89,600  =  constant;  T=  thickness  of  plate  in  inches; 
D  =  outside  diameter  of  furnaces  in  inches ;  L  =  length  of  fur- 
naces in  feet. 

If  rings  are  fitted  around  the  furnaces,  the  length  to  be  taken 
between  rings,  and  pressure  not  to  exceed 

8,000  X  T 
D 

The  machinery  and  boilers  of  steam  yachts  are  to  be  surveyed 
annually  if  practicable,  and  in  addition  to  be  submitted  to  a  special 
survey  every  four  years  and  the  boilers  to  special  survey  when  six 
years  old  and  subsequently  to  annual  survey. 

If  satisfactory,  these  surveys  will  be  recorded  in  the  Yacht  Regis- 
ter thus : 


134 


Extracts  from  Lloyd's  Rules. 


"Lloyd's  M.  C.  5,  80"  in  red,  or  "B.  &  M.  S.  5,  80"  in  red. 

"Lloyd's  M.  C."  (Lloyd's  Machinery  Certificate),  denotes  that  the 
machinery  and  boilers  are  fitted  in  accordance  with  these  Rules,  and 
were  found  upon  examination  at  the  time  to  be  in  good  condition. 

"B.  &  M.  S."  (boilers  and  machinery  surveyed)  with  a  date, 
denotes  that  the  boilers  and  machinery,  though  not  fitted  strictly  in 
accordance  with  these  Rules,  were  found  upon  inspection  at  that 
time  to  be  in  good  condition. 

"B.  S."  (boilers  surveyed)  with  a  date,  denotes  that  the  boilers 
were  found  upon  inspection  at  that  time  to  be  in  good  condition. 

SCANTLING  FOR  WOOD  BUILT  YACHTS. 


Ton- 
nage. 

Spacing 
for 
Double 
Frames. 

Floors 
Sided. 

Frames 
sided  and 
moulded 
at    floors. 

Frames 
moulded 
at  deck. 

Keel, 
stem  post 
deadwood 
sided. 

Outside 
planking. 

Deck 
plank. 

Sectional 
area  of 
shelf. 

Clamps, 
bilge 
streak. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

20 

18 

4 

3^ 

2^ 

5K 

1# 

i'/ 

14 

^4, 

50 

20 

5K 

4* 

3* 

7^ 

2 

2* 

25 

2 

IOO 

23 

6^ 

^ 

3* 

9 

2* 

2^ 

40 

2^ 

200 

24 

7% 

63^ 

4* 

10 

2K 

23^ 

55 

2^ 

4OO 

26 

9^ 

8 

5 

n 

3 

3 

75 

3 

Deck  beams  are  proportioned  according  to  the  breadth  of  the 
vessel.  For  8ft.  beam,  they  should  be  2^  in.  square;  for  12  ft., 
4>^  in.;  for  16  ft.,  6in.;  for  20  ft.,  7  in.;  for  24ft.,  8  in.,  with  reduc- 
tion at  ends.  Spacing  of  beams  to  be  24,  30,  38,  42  and  46  in. 
respectively.  A  vessel  of  20  tons  should  have  4  pairs  of  hanging 
knees  to  upper  deck  beams;  one  of  50  tons,  5  pair;  one  of  100  tons, 
8  pair;  one  of  200  tons,  13  pair,  and  one  of  400  tons,  18  pair. 

Bolts  through  heel  knee,  deadwood,  keelson,  transoms,  breast- 
hooks  and  lower  deck  knees  should  be  about  }£  in.  for  20  tons ; 
It  for  50  tons;  if  for  100  tons;  H  to  i  in.  for  200  tons  and  If  to 
i-jiy  for  400  tons. 

Bolts  through  shelf,  clamp  and  arms  of  knees  should  be  about 
A  for  20  tons  ;  If  for  50  tons ;  H  for  100  tons ;  H  for  200  tons  and 
the  same  for  400  tons. 


Extracts  from  Lloyd's  Rules. 


135 


Bolts  through  heels  of  frames,  upper  deck  shelf  and  clamp,  and 
upper  deck  knees  are  of  the  same  diameter. 

Bilge  and  through  butt  bolts  A  for  20  tons  ;  A  for  100  tons  ;  i  £  for 
200  tons  and  H  for  400  tons. 

Hardwood  treenails  should  be  i  in.  for  100  tons  and  1^6  for  400 
tons. 

Steam  yachts  of  20  tons  should  have  2  anchors  about  100  and 
85  Ibs.  with  at  least  A  studded  chain  or  its  equal  in  close-link.  For 
50  tons,  there  should  be  3  anchors  of  200,  150  and  84  Ibs.,  with  it  chain. 
For  100  tons,  3  anchors,  the  largest  about  350  Ibs.  with  H  chain; 
for  200  tons,  4  anchors,  the  largest  about  525  Ibs.  with  it  chain  ;  for 
400  tons,  5  anchors,  the  largest  1,000  Ibs.  with  i^  chain.  Anchor 
stocks  to  weigh  about  one-quarter  additional.  Length  of  chain 
should  run  from  45  to  75  fathoms. 


SCANTLING   FOR  IRON   BUILT  YACHTS. 


No.  for  Frames, 
Reverse  Frames 
and    Bulkheads. 

Angle  Iron 
Frames. 

Reverse  Frames. 

Floors. 

Bulkheads. 

20       to  22.5 

i  x  iK  x  A 

7  X  A 

25.5  to  28 

a 

x  i#  x  A 

I>£  X  I>£  X  A 

9X  A 

30      to  31.5 

2J 

{x*l4  x  A 

2        X  I  ^4   X   i  6" 

ii  x  A 

A 

33-5  to  37 

i  x  2^  x  A 

2#  X  2%  X  A 

12  x  A 

A 

40.5  to  43.5 

3 

x  2^  x  A 

2^  X  2%  X  A 

14  x  A 

A 

45-5  to  47.5 

3 

x  2%  x  A 

2^  X  2^  X  A 

15  x  A 

5i       to  54 

3 

x  3    x  A 

2*4  x  2*4  x  A 

16  X  A 

A 

Numbers  for 
keel,  stem,    post 
and  plating. 

.ri 

Keel,  stem, 
sternpost. 

if 

Keelson  and 
Stringer 
angle  irons. 

Stringer 
plate  or 

deck 

11 

•*  T3 

.«o 

meter  of 
dcr-head. 

o 

w  — 

beams. 

JS   ° 

.-  '.  ; 

H  ? 

Q  2 

In. 

In. 

In. 

In. 

900  to    1,200 

18 

4}4  X    H 

2        X  2        X  A 

8  X  A 

1,500  to   i,  800 

18 

4j4  X    % 

~h 

2^  X  2^  X  A 

10  x  A 

2$ 

2 

2,050  to  2,300 

20 

5      X    ft 

A 

2^  x  2^  x  A 

13  x  A 

2/4 

2*4 

2,600  to  3,100 

20 

A 

3      X  2^  X  A 

15  x  A 

2*4 

2$ 

3,900  to  4,650 

21 

6/4  X  i/£ 

A 

3      X  2^  X  A 

I8XA 

2^4 

3$ 

5,350  to  6,000 

22 

6^  X  i/£ 

A 

3l/2  X  2%  X  A 

22  X  A 

2}£ 

3$ 

7,300  to   8,500 

22 

7      Xitf 

A 

3K  X  3      X  A 

28  x  A 

3 

4/8 

136  Extracts  from  Lloyd's  Rules. 

Middle  line  keelsons  of  plate  iron  from  fa  to  -fa  thick  are  required 
in  yachts  whose  number  is  above  3,100.  Tie  plates  must  also  be 
worked  over  the  beams.  They  are  the  same  thickness  as  the 
stringer  plates,  but  a  little  narrower.  Garboard  plates  are  -fa  thicker 
than  side  plating  up  to  number  2,050  and  A  thicker  above  that. 
Stem,  post  and  keel  to  be  double  riveted  when  plating  is  over  -fa 
thick.  Butts  of  plating  and  stringers  double  riveted  when  over  A 
thick.  Upper  edge  of  garboards  and  sheer  strake  double  riveted 
over  when  -fa  thick. 

Beams  are  proportioned  to  the  breadth  of  the  vessel.  For  8ft. 
breadth,  the  beams  should  be  2%  X  2  x  -fa  angle  iron;  for  12  ft., 
they  should  be  3^  X  2^  x  -fa ;  for  i6ft.,  beams  are  4^  X  3  X  A; 
for  20  ft.,  they  are  of  5  X  A  in.  bulb  iron  and  for  24ft.,  of  6  x  A  bulb 
iron. 

Rivets  must  be  their  own  diameter  from  end  of  plate  at  butts  and 
the  rows  must  be  one  and  a  half  diameter  apart  in  edge  riveting. 
They  should  be  spaced  four  and  a  half  diameters  apart  from  center 
to  center  in  plating  and  from  five  to  seven  diameters  apart  in.  angle 
iron  work.  Rivets  for  A  iron  are  ^  in.  diameter ;  for  -fa  iron,  they 
are  f£  diameter  and  for  ii  they  are  J/%  in.  No  plates  for  the  vessel's 
side  to  be  less  than  five  frame  spaces  in  length.  No  butts  of  plating 
in  adjoining  strakes  to  be  nearer  than  two  spaces,  and  the  butts  of 
alternate  strakes  to  shift  not  less  than  one  frame  space.  All  butts 
throughout  the  vessel  should  be  given  good  shift,  as  a  line  of  butts 
is  a  line  of  weakness. 


VIII. 
RACING     STEAM     YACHTS. 

THE  crudest  method  of  racing  steam  yachts  is  to  start  all  vessels 
at  the  same  instant  and  note  the  times  of  arrival,  making  no 
allowances  of  any  sort.  The  result  determines  which  is  absolutely 
the  speediest  yacht,  without  reference  to  the  means  by  which  the 
speed  has  been  produced  or  the  possibilities  for  speed  possessed  by 
vessels  differing  in  hull  and  driving  power.  Such  tests  have  interest 
for  a  time,  but  would  not  promote  competition  nor  furnish  any  desir- 
able information  concerning  the  economics  of  form  in  hull  or  engine 
performance.  It  would  soon  become  evident  that  the  longest  or 
largest  yacht  would  have  an  undue  advantage  from  the  greater  pos- 
sibilities inherent  in  mere  size,  providing  always  that  due  advantage 
has  been  taken  of  the  possibilities  by  the  designing  engineer.  The 
entries  would  rapidly  diminish,  as  none  but  the  largest  would  have 
any  chance  in  such  competition.  The  races  would  leave  us  none  the 
wiser  in  the  end. 

If,  however,  a  shorter  or  smaller  vessel  should  demonstrate  herself 
absolutely  faster  than  a  longer  competitor,  she  would  receive  credit 
therefor  in  her  victory.  But  the  amount  by  which  she  actually  beat 
the  larger  boat  would  not  truly  represent  her  superiority,  for  the 
victory  was  gained  upon  a  less  length,  and  therefore  upon  smaller 
possibilities  so  far  as  hull  is  concerned.  An  allowance  for  this  differ- 
ence in  length  of  the  competitors  would  in  justice  have  to  be  added, 
so  that  the  absolute  amount  by  which  the  smaller  yacht  distanced 


138 


Racing    Steam    Yachts. 


her  larger  rival,  may  be  augmented  in  proportion  to   her  lack  of 
length. 

It  is  upon  this  consideration  that  the  "  Emory  Tables  "  have  been 
compiled.  Chief  Engineer  F.  B.  Isherwood,  U.  S.  N.,  counselled  an 
allowance  based  upon  the  assumption  that  speeds  will  or  should  vary 
as  the  cube  root  of  the  loadline  lengths,  and  Mr.  C.  E.  Emory  found 
that  by  multiplying  the  cube  root  of  the  length  by  2.7  it  would  very 
nearly  express  the  actual  speed  attained  by  yachts  of  normal  form 
and  power,  or  2.7  3yT~" 

TIME    ALLOWANCE    FOR    LENGTH    BY   EMORY 
FORMULA. 


Length  of  loadline. 

Time  required  to  run 
80  knots. 

Length  of  loadline. 

Time  required  to  run 
80  knots. 

Feet. 

H.  M.  S. 

Feet. 

H.  M.  S. 

50 

8  02  33 

1  80 

5  17  5i 

55 

7  47  28 

185 

5  14  53 

60 

7  33  42 

190 

5  12  oo 

65 

7  21  32 

195 

5  09  14 

70 

7  10  57 

200 

5  06  35 

75 

7  oi  38 

205 

5  03  59 

80 

6  51  49 

2IO 

5  oi  32 

85 

6  44  49 

215 

4  59  05 

90 

6  36  42 

220 

4  56  44 

95 

6  29  53 

225 

4  54  29 

100 

6  23  oi 

230 

4  52  19 

105 

6  16  50 

235 

4  50  10 

no 

6  ii  02 

240 

4  48  06 

115 

6  05  33 

245 

4  46  05 

120 

6  oo  25 

250 

4  44  07 

125 

5  55  40 

255 

4  42  12 

130 

5  50  55 

26O 

4  38  33 

135 

5  46  34 

265 

140 

5  42  15 

270 

4  35  05 

145 

5  38  21 

275 

150 

5  34  36 

280 

4  3i  47 

155 

5  30  58 

285 

160 

5  27  27 

290 

4  28  36 

165 

5  24  09 

295 



170 

5  20  53 

3OO 

4  25  35 

175 

5  17  5i 

The  foregoing  allowance  is  really  only  one  for  the  hull,  and  would 
be  fair  and  all  that  is  required  upon  the  assumption  that  in  every 


Racing   Steam    Yachts.  139 

steam  yacht  built,  every  quality  is  sacrificed  to  the  sole  attainment 
of  the  highest  speed.  But  this  is  manifestly  not  the  case,  and  the 
assumption  would  in  the  long  run  be  fraught  with  evil  consequences 
to  the  sport.  In  the  Emory  Rule,  it  is  assumed  that  upon  any  given 
length,  the  motive  power  will  take  up  the  same  proportion  of  the 
displacement,  and  that  an  addition  to  displacement  means  additional 
opportunity  for  increasing  weight  of  motive  power.  These  are  two 
suppositions  which  will  not  always  hold. 

In  the  first  place,  many  steam  yachts  are  intended  to  meet  other 
requirements  than  the  maximum  speed  only.  They  will  differ  in 
strength  of  construction,  according  to  the  service  they  are  to  undergo. 
It  would  be  unwarranted  and  reckless  to  construct  a  seagoing  steamer 
in  the  same  light  and  trifling  way  that  high  speed  launches  and 
smooth-water  craft  are  produced.  More  solid  structure,  more  free- 
board, stores,  coal  bunker  capacity,  rig,  equipment  and  varying 
demands  as  to  accommodations,  necessarily  destroy  the  correctness 
of  the  assumption  in  the  Emory  Rule,  that  motive  power  will  bear 
the  same  proportion  to  displacement  in  all  yachts  of  like  length. 
Economy  in  space  taken  up  by  engines  and  boilers  and  small  coal 
consumption,  which  are  of  great  importance  to  cruising  yachts,  will 
frequently  place  another  limit  upon  the  motive  power,  as  also  con- 
siderations of  first  cost  and  subsequent  running.  Thus  it  will  be 
seen  that  individual  yachts  will  not  necessarily  meet  the  conditional 
characteristics  upon  which  the  equity  of  the  Emory  Rule  rests. 

The  direct  tendency  of  the  Rule  will  be  to  banish  from  the  start 
all  but  avowed  "racing  machines,"  and  in  these  the  weight  of 
structure  and  equipment  will  be  reduced  to  a  minimum,  rendering 
the  vessels  unreliable,  if  not  actually  unsafe,  and  certainly  unfit  to 
meet  the  needs  of  the  seagoing  cruiser.  Yachts  of  normal  propor- 
tions, normal  power  and  high  performance  as  to  engine  economy 
would  not  be  countenanced  under  the  Emory  Rule.  Nor  would 
efforts  in  behalf  of  improvement  in  performance,  which  are  at  least 
equally  as  important  as  the  maximum  possible  speed  on  the  length, 
be  given  any  consideration.  So  far  from  furthering  advance  in 
engineering  questions,  a  "  length  rule  "  would  rather  promote  the 
most  costly  and  wasteful  machinery,  the  "  speed-at-any-price  "  style 


140  Racing    Steam     Yachts. 

of  yacht,  poorly  suited  to  the  much  wider  field  which  legitimate 
steam  yachting  should  really  command. 

In  the  <Emory  Rule,  the  competitive  equity  must  be  deemed  as 
carried  out  only  half  way.  If  two  yachts  of  like  length  meet  and 
race  over  a  course  in  equal  time,  they  would  pass  off  as  equally 
efficient  under  the  "length  rule."  Yet  one  of  the  yachts  may  have 
accomplished  the  distance  upon  less  expenditure  of  power,  showing 
that  her  model  or  machinery  is  in  reality  the  superior  of  the  two.  In 
equity,  and  for  an  intelligent  appreciation  of  the  competition,  this 
superiority  should  be  made  evident  in  a  tangible  way  for  true  com- 
parison of  performance,  otherwise  the  relative  perfection  of  model 
and  machinery  between  the  two  yachts  would  be  lost  sight  of. 
Evidently  an  allowance  for  the  smaller  expenditure  of  power  is  a 
proper  correction  to  apply,  thereby  ascribing  to  the  boat  expending 
least  power  that  superiority  in  performance  which  is  really  hers. 

The  Emory  rule  is  also  lacking  in  other  material  respects.  If  two 
yachts  of  like  length  are  driven  by  like  power,  it  stands  to  reason 
that  a  fine  form  will  have  greater  possibilities  from  the  very  start 
than  a  fuller  form  of  hull,  as  the  extra  displacement  of  the  latter  does 
not  necessarily  go  to  greater  driving  power,  and  in  this  example  may 
be  supposed  to  be  expended  in  a  structure  of  sea-going  scantling 
and  in  storage  for  distant  cruising.  Manifestly,  such  a  vessel  should 
in  equity  be  entitled  to  an  accounting  for  the  greater  bulk  or  volume 
she  has  driven  through  the  water  with  like  speed  and  like  power. 
Her  performance  is  certainly  more  creditable  "under  these  supposi- 
tions than  that  of  her  finer  lined  opponent.  Yet  competition  under 
"length  measurement"  would  rob  the  fuller  boat  of  the  credit  she  is 
justly  entitled  to,  and  in  so  doing  would  fail  to  disclose  a  true 
understanding  of  the  respective  merits  of  the  two  vessels. 

If  the  racing  of  steam  yachts  is  to  be  viewed  simply  as  a  rough 
lumping  together  of  vessels  of  various  sizes  (lengths)  with  a  view  to 
distributing  prizes  to  the  first  boat  across  the  finish,  regardless  of  the 
real  merits  of  performance,  the  Emory  Rule  will  be  sufficient,  though 
it  will  confine  racing  to  a  few  "machines  "  when  its  working  is  fully 
comprehended. 

But  if  racing  steam  yachts  is  to  be  placed  upon  a  higher  plane  of 


Racing    Steam     Yachts.  141 

justice  and  engineering  utility,  and  permit  comparative  tests  between 
all  varieties  without  prejudice  to  some  and  a  premium  upon  others, 
then  it  is  manifest  that  "  length  measurement "  must  be  replaced  by  a 
rule  which  shall  take  due  consideration  of  displacement  and  power 
as  well  as  length.  The  length  must  still  be  included,  for  it  is  well 
known  that  a  given  displacement  in  a  long  form  has  greater  pos- 
sibilities for  speed  than  if  placed  in  a  shorter,  chubbier  form,  at  least 
within  such  proportions  as  have  been  practically  exploited  at  this 
day. 

If  one  vessel  has  a  larger  displacement  than  another  of  the  same 
length,  and  that  excess  of  displacement  has  been  utilized  in  greater 
weight  of  engine  and  more  driving  power,  the  excess  of  power  ex- 
pended over  the  course  will  pay  under  the  proposed  rule  its  just 
share  for  the  greater  possibilities  possessed  in  the  excess  of  displace- 
ment as  expressed  in  the  increased  power. 

Mr.  Chas.  H.  Haswell,  Measurer  of  the  American  Yacht  Club, 
has  contributed  a  rule  which  comes  near  to  satisfying  the  above 
train  of  reasoning  and  also  seeks  to  cover  the  features  of  natural  and 
forced  draft.  Mr.  Haswell  accepts  the  old  formula  of  naval 
architecture  that  speed  will  be  proportional  to  the  cube  root  of  the 
power  divided  by  the  area  of  the  midship  section,  or  else  by  the  two- 
thirds  power  of  the  displacement.  The  length  receives  no  consider- 
ation. Yet  of  two  vessels  having  the  same  midship  section,  the 
longer  has  a  fundamental  advantage,  and  the  same  can  be  said  of 
displacement.  Hence,  the  introduction  of  length  as  a  factor  in  a 
just  formula  is  a  necessity. 

It  will  not  do  to  say  it  is  the  business  of  the  builder  to  distribute 
this  displacement  or  cross-section  upon  the  most  advantageous 
length,  for  such  proportions  would  lead  to  the  construction  of 
"machines"  and  drive  out  of  existence  the  normal  steam  yacht  upon 
the  propagation  of  which  the  popularity  and  usefulness  of  steam 
yachting  mainly  depend. 

The  designer,  who  from  other  considerations  than  speed,  is  forced 
to  choose  a  less  favorable  length  to  the  displacement  or  cross- 
section,  should  not  be  "boycotted"  from  the  line,  for  his  production 
may  in  fact  be  more  creditable  from  an  engineer's  or  yachtsman's 


142  Racing   Steam     Yachts. 

standpoint,  though  not  as  fast  as  the  "machine  "  when  compensation 
is  given  under  a  rule  prejudicial  to  one  and  favorable  to  another 
regardless  of  intrinsic  merit  of  performance, 

Mr.  Haswell  explains  his  method  of  determining  allowances  as 
follows  : 

The  end  desired,  that  is,  a  comparison  of  volume,  can  be  attained 
with  all  sufficient  accuracy  and  with  more  facility  by  taking  the 
gross  Custom  House  tonnage,  as  computed  either  by  United  States 
or  British  laws,  which  is  a  fair  exponent  of  the  volume  of  the  hull  of 
a  vessel. 

To  arrive  at  the  other  element,  that  of  actual  power,  by  the  com- 
putation of  it  from  an  engine  by  its  operation,  involves  time  and 
much  labor,  in  addition  to  the  difficulty  of  deriving  reliable  assist- 
ance from  the  driver  of  the  engine  to  develop  the  full  power  of  the 
boiler,  as  shown  by  the  operation  of  the  engine,  when  the  develop- 
ment of  it  is  to  operate  to  the  disadvantage  of  his  employer. 

The  determination  of  the  capacity  or  power  of  a  boiler  would  be 
best  attained  by  ascertaining  the  exact  volume  or  weight  of  water 
evaporated,  or  fuel  consumed  in  an  assigned  period  ;  but  inasmuch 
as  to  attain  these  results  would  involve  expensive  attachments  to  a 
boiler,  labor  and  time,  and  be  exposed  to  the  objections  already 
referred  to  in  relation  to  the  engine  driver  and  his  assistants  in 
interest  of  their  employer,  both  of  these  methods  would  seem  to  be 
impracticable  of  adoption. 

In  order,  then,  to  exclude  all  elements  of  variation,  all  dependence 
upon  the  integrity  of  operatives,  and  to  operate  only  with  such 
elements  as  combine  the  greatest  uniformity,  facility  and  practica- 
bility of  attainment,  and  assuming  that  the  speed  of  similar  vessels 
is  as  the  cube  root  of  their  moments,  I  submit  as  follows : 
The  accepted  formulas  for  the  speed  of  steam  vessels : 

3  3  . . 

V-?-  and    V^-  each  =  V. 
D% 

P  representing  the  horse  power ;  A  area  of  immersed  amidship 
section,  in  square  feet ;  D  displacement  of  hull  in  tons  ;  and  V 
velocity  of  vessel  in  miles  per  hour ;  the  former  when  the  area  of 


Racing    Steam    Yachts.  143 

amidship  section  is  taken,  and  the  latter  when  the  displacement  of 
the  hull  is  taken. 

The  boiler,  that  is  the  area  of  the  grate  surface,  and  the  character 
of  its  construction  and  combustion,  are  the  essential  elements  of  the 
power  of  a  steam  vessel.  The  dimensions  of  the  engine  are  arbi- 
trary and  secondary. 

Thus,  with  like  and  equal  boilers,  the  attached  engines  may  be  of 
different  diameters  and  stroke,  the  propellers  of  different  areas  and 
pitch  of  blades,  yet  the  power  under  like  combustion  is  constant. 
The  manner  of  utilizing  it  by  high  or  low  expansion,  by  high  or  low 
velocity  of  piston  and  of  propeller,  is  arbitrary;  and  in  the  attain- 
ment of  the  best  results  with  the  least  means,  is  the  field  of  compe- 
tition ;  as  in  the  manner  of  two  sailing  vessels  of  like  designs  and 
similar  capacities,  one  may  be  rigged  taunt,  with  light  canvas,  the 
other  square,  with  heavy  canvas,  the  competition  would  be  in 
arriving  at  that  sparring,  rig  and  fitting  which  is  most  effective. 

If  the  manner  of  combustion  in  steam  boilers  was  uniform,  com- 
putation of  their  power  as  determined  by  the  area  of  their  grate 
would  be  very  simple,  but,  inasmuch  as  there  are  four  manners  of 
operating  them,  it  becomes  necessary  to  assign  a  specific  rate  or 
factor  for  each ;  thus,  there  is  combustion  by  natural  draft,  steam 
jet,  blast  and  exhaust,  whereby  the  effect  or  capacity  of  grate  surface 
is  materially  altered,  and  if  their  relative  effects  can  be  arrived  at 
with  any  reasonable  accuracy,  the  problem  of  relative  capacities  of 
steam  yachts  is  very  satisfactorily  attained. 

From  experiments  lately  conducted  in  England  with  boilers  of  two 
steamers,  to  determine  the  relative  effects  of  different  manners  of 
combustion,  the  results  were  as  follows : 

Natural  draft,  i ;  jet,  1.25;  blast,  1.6.  Adopting  these  figures  as 
fair  exponents  of  the  case,  the  grate  surface  of  a  yacht  then  should 
be  multiplied  by  the  factor  due  to  the  manner  of  combustion  to 
arrive  at  the  power,  and  the  volume  of  the  vessel  in  tons,  being 
taken  to  represent  her  mass,  it  remains  then  only  to  reduce  these 
elements  to  a  standard  of  comparison  in  order  to  assign  a  just 
allowance  of  time  for  the  difference  of  the  elements;  and  in  order 
to  arrive  at  this,  and  assuming  the  second  formula  above  given,  viz., 


144  Racing   Steam    Yachts. 

that  the  speed  of  a  steam  vessel  is  as  the  cube  root  of  the  square  of 
her  displacement  in  tons,  then  for  power  of  engine  substitute  area  of 
grate,  due  to  the  method  of  combustion,  and  it  remains  but  to 
decide  upon  the  allowance  of  time  for  the  greater  capacity  to  give 
the  less  in  each  class,  and  which  results  may  be  satisfactorily  arrived 
at  by  a  summary  of  the  elements  and  speed  of  a  number  of  vessels. 

In  illustration  of  this  method,  I  submit  two  yachts,  having 
capacities  and  powers  as  follows  : 

No.  i.  80  tons,  40  sq.  ft.  of  grate,  with  a  blast  draft,  =  40  x  1.6 
=  64  sq.  ft.  Then 


No.  2.     70  tons,  50  sq.  ft.  of  grate,  natural  draft,  =  50.     And 

2.94  _  1.433. 


3 3  3 

/y/  5°     ==  \/— 5—  - 


Which  results  would  represent  their  competitive  capacities.     Assum- 
ing then  the  speed  of  No.  i  to  be  14  knots  per  hour 

6,120  x  14 

=  1,428  ft.  per  minute  ; 

60 

and  that  No.  2  will  be  as  1.511  :  1.433  ::  J>428  :  i,354-ft. 

Then,  if  1,354 ft.  require  one  minute,  74  (1,428  —  1,354)  will 
require  .05466  minute  more  time  to  attain  a  like  distance,  =  .05466 
X  60  =  3.2796  minutes  per  hour,  and 

.05466 

=  .003904  per  minute. 

14 

Hence,  for  course  of  50  nautical  miles,  the  allowance  No.  i  would 
have  to  give  No.  2,  would  be  .003904  X  60  (minutes  per  hour),  and 
by  50  (miles)  =  11.712  minutes. 

Inversely:     6,120  X  50  =  306,000 ft.,  and 

306,000 

=  214.3  minutes, 

1,354 
the  time  of  No.  i  performing  the  distance,  and 

306,000 

=  225.9  rninutes, 

i,354 
the  time  of  No.  2  performing  the  distance.     Hence,  225.9  —  2I4-3 


Racing   Steam    Yachts.  145 

=  11.6  minutes,  difference  or  allowance  to  be  given  for  a  distance 
of  50  miles. 

In  the  application  of  the  first  formula  to  attain  V  or  speed  of 
vessel,  it  is  usual  to  .add  a  coefficient  to  the  numerator,  which 
represents  the  relative  capacity  of  performance. 

In  the  case  under  consideration  it  is  not  the  velocity  that  is 
required,  but  the  elements  that  produce  it,  and  the  coefficient  is  the 
representation  of  the  competitive  capacity  of  the  yacht.  Thus,  the 
finer  the  model  the  more  effective  the  instrument  of  propulsion,  as 
a  propeller  or  side-wheels,  and  the  less  the  friction,  both  of  the 
engine  and  the  wet  surface  of  the  hull,  the  greater  is  the  coefficient ; 
or,  in  other  words,  the  more  effective  the  result  attained,  and  as  this 
coefficient  is  peculiar  to  each  and  every  vessel,  it  is  of  value  only 
when  known,  and  consequently,  except  in  a  general  application  to 
like  types  and  like  proportions  of  vessels,  it  is  useless. 


IX. 


MANAGEMENT     AND     CARE     OF 
MACHINERY. 

FILLING  UP  THE  BOILER.— Cold  water  pumped  into  hot 
boilers  is  very  injurious,  causing  severe  contraction  of  the 
seams  and  stays,  which  very  often  leads  to  fracture  of  the  stays  or 
leakage  in  the  seams  and  tubes.  Many  boilers,  well  constructed  and 
of  good  material,  have  been  ruined  by  being  blown  out  under  a  high 
pressure  of  steam,  and  then  immediately  filled  with  cold  water.  The 
boiler  should  be  allowed  to  cool  down  first.  A  mark  on  outside  of 
boiler  and  on  the  water  glass  should  indicate  the  height  of  the 
crownsheet,  so  that  the  fireman  may  be  certain  of  carrying  the  water 
level  high  enough  to  avoid  exposure.  If  no  such  mark  has  been 
made,  fill  up  the  boiler  and  with  the  manhole  open  make  the  neces- 
sary observation  and  transfer  the  measurement  to  outside  of  boiler 
and  from  that  to  the  water  glass. 

LIGHTING  FIRES. — Fires  should  not  be  started  until  the  boiler  has 
been  pumped  full.  If  too  much  water  has  been  pumped  in,  blow  off 
by  the  bottom  valve,  after  the  water  is  partly  heated.  This  will  with- 
draw cold  water  from  the  bottom  and  start  the  circulation.  Start 
the  fires  in  ample  time  and  do  not  force  them  with  cold  water  in  the 
boiler.  The  grate  should  be  kept  well  covered  with  a  thin  fire.  Do 
not  feed  with  large  lumps  or  too  much  at  a  time,  or  keep  the  fire 
door  open  too  long.  Keep  the  grate  free  from  clinker,  so  that  the 
draft  may  not  be  impaired.  The  fires  are  started  by  splitting  a  quan- 


Management  and  Care  of  Machinery.          147 

tity  of  wood  and  distributing  it  with  shavings  and  oily  cotton  waste 
over  the  grate.  When  this  has  reached  a  blaze  and  the  ashes  glow, 
introduce  a  little  fine  coal  without  smothering  the  wood  fire.  Cotton 
waste  should  not  be  kept  stored  up  for  this  purpose,  however,  as  it 
is  liable  to  spontaneous  combustion. 

A  slow  rate  of  cumbustion  with  moderate  draft  produces  a  better 
evaporative  result  than  when  the  fires  are  urged.  The  test  of  a  good 
fire  is  in  the  glow  of  the  ashpit.  When  the  ashes  in  the  pit  appear 
dull,  the  fire  needs  cleaning,  but  it  should  not  be  broken  up.  The 
bars  should  be  evenly  covered  and  no  space  left  bare,  as  a  cold 
current  of  air  would  draw  up  and  sweep  over  the  fire,  cooling  it 
down.  In  boilers  with  two  furnaces  attend  one  at  a  time.  Bitumin- 
ous coal  is  apt  to  form  a  crust  on  the  surface,  and  before  feeding 
should  be  broken.  Avoid  heaping  the  fuel  at  the  front,  and  do  not 
clean  a  fire  down  too  low,  as  it  will  take  some  time  to  come  up 
again. 

SAFETY  VALVE. — Raise  the  safety  valve  to  permit  hot  air  to  escape. 
When  a  few  pounds  pressure  are  shown  on  the  gauge,  open  stop  and 
throttle  valve  and  allow  steam  to  pass  through  the  engine  to  warm 
up  its  parts.  Sudden  admission  of  high  steam  to  the  cold  engine 
would  cause  such  expansion  to  packing  of  piston  and  other  light 
parts  that  free  working  will  be  endangered.  When  steam  is  up,  the 
fires  should  be  so  managed  that  the  safety  valve  will  not  blow  off, 
although  the  point  of  blow-off  should  first  be  compared  with  the 
steam  gauge. 

If  the  boiler  steams  too  fast,  close  the  damper  and  shut  off  draft, 
but  do  not  throw  open  the  furnace  door  if  it  can  be  avoided. 

FOAMING  OR  PRIMING. — This  is  the  violent  ebullition  of  the  water 
at  the  surface,  and  is  caused  by  irregular  feed,  sudden  withdrawal  of 
steam,  as  upon  opening  the  throttle  wide  at  once,  or  from  dirty 
water.  Also  from  the  presence  of  grease,  especially  in  new  boilers. 
Most  frequently  the  trouble  is  with  the  manner  of  feeding.  To 
avoid  taking  foam  over  into  the  steam  pipe,  the  under  side  of  the 
dome  is  protected  by  perforated  plate,  or  the  supply  pipe  is  extended 
the  length  of  the  boiler  inside  and  perforated,  so  as  to  take  the 
steam  from  the  whole  length  and  not  from  one  spot.  Wash  plates 


148         Management  and  Care  of  Machinery. 

are  also  sometimes  fitted  in  the  boiler  near  water  level,  and  a  trap  on 
the  pipe  between  boiler  and  engine,  to  catch  the  watery  particles 
before  reaching  the  engine.  To  check  priming,  close  throttle  valve 
long  enough  to  show  true  level  of  water.  If  sufficiently  high,  blow 
from  the  surface  and  turn  on  feed.  In  case  of  violent  foaming 
caused  by  dirty  water,  or  change  from  fresh  to  salt  or  the  opposite, 
check  draft  in  addition  and  cover  the  fires  with  fresh  coal.  In  other 
words,  cool  down  the  fire  so  that  the  ebullition  may  cease.  If  grease 
is  the  cause,  common  washing  soda  pumped  into  the  boiler  will  stop 
it.  Feed  water  should  not  be  taken  from  greasy  tank  or  oil  barrel. 
Carrying  the  water  too  high  is  another  cause  of  priming,  as  it  reduces 
the  steam  space.  Boilers  with  insufficient  steam  space  are  liable  to 
frequent  priming. 

THE  FEED. — The  working  of  the  feed  can  be  followed  by  the  rise 
in  the  water  glass.  If  there  are  doubts  about  it,  feel  the  pipe  near 
the  check  valve.  If  it  warms  up,  the  check  is  at  fault,  for  back 
water  is  escaping  from  the  boiler.  By  placing  the  ear  close  to  the 
valve,  the  click  of  the  valve  can  be  detected.  If  it  is  working,  look 
about  for  some  source  of  escape  in  the  boiler.  Examine  the  blow- 
off  cocks  and  other  connections  to  ascertain  if  they  are  closed.  Then 
turn  to  the  piping  and  look  for  a  leak  in  the  pump  delivery  or 
suction,  or  the  stopping  up  of  the  latter.  A  burst  can  be  temporarily 
repaired  by  wrapping  it  with  canvas  coated  with  white  lead  and 
serving  it  over  with  marline  or  twine.  For  a  long  split  lay  a  strip  of 
wood  or  iron  on  before  applying  the  canvas.  The  feed  pump  should 
not  be  allowed  to  heat  up  from  too  close  proximity  to  the  boiler,  or 
from  undue  friction  of  working  parts,  or  from  drawing  the  suction 
too  hot  from  the  hot-well.  A  heated  pump  will  generate  vapors 
which  prevent  the  valves  from  working  free  in  the  plunger  cylinder. 

Low  WATER. — Should  the  water  meanwhile  run  down  in  the 
boiler,  draw  the  fire  and  leave  furnace  door  open,  or  bank  the  fires 
or  cover  with  fresh  coal  and  leave  furnace  door  open.  But  if  the 
crown  sheets  are  supposed  to  be  overheated,  cover  the  fire  with 
damp  ashes,  open  door  and  close  the  damper.  Under  no  circum- 
stances turn  on  the  feed  full  speed  and  force  cold  water  over  the  hot 
sheets,  should  it  suddenly  be  found  to  work.  This  is  a  frequent 


Management  and  Care  of  Machinery.          149 

cause  of  explosions.  A  very  slow  feed  may  be  kept  up,  if  it  has  been 
going  at  the  time,  but  if  engine  and  feed  have  been  stopped  do  not 
start  them,  as  a  sudden  commotion  in  the  boiler  might  cause  disaster. 
If  the  engines  are  going,  do  not  interfere,  and  do  not  suddenly  lift 
the  safety  valve,  as  the  boiler  should  be  left  at  rest  under  the  circum- 
stances and  not  be  submitted  to  any  violent  disturbance.  When  the 
boiler  has  cooled  a  little,  the  safety  valve  may  be  lifted  gently  and 
the  engines  started  to  run  down  the  steam.  The  fire  should  not  be 
drawn  in  the  extreme  case  of  hot  crown  sheet,  because  much  heat 
would  be  liberated  during  the  attempt.  It  is  better  to  smother  it 
and  open  the  smoke-box  door  to  draw  cold  air  through  the  tubes. 
In  hastily  drawing  fires,  the  hot  coal  is  dumped  in  front  of  the 
boiler,  and  the  fireman  finds  he  cannot  complete  the  work,  owing  to 
the  heat  rising  from  the  pile.  He  is  then  in  trouble  and  apt  to  lose 
his  head  and  quit  his  post,  demoralizing  those  around  him. 

After  steam  has  run  down,  the  boiler  must  be  emptied  and 
examined  by  a  person  capable  of  estimating  the  damage  before  risk- 
ing a  fresh  start. 

With  proper  gauge,  cocks  and  low  water  alarm,  frequently  tested, 
only  gross  negligence  or  incompetency  can  bring  about  overheated 
crown  sheets,  and  even  then  the  fusible  plug  should  avert  danger  if 
it  has  been  properly  attended  to. 

INSPIRATOR  FAILS  TO  FEED. — If  the  steam  pipe  *s  full  of  hot 
water  when  the  Hancock  Inspirator  is  to  be  started,  open  the  steam 
valve  sufficiently  to  allow  the  water  to  pass  off  through  the  inspirator 
and  out  at  the  overflow.  If  the  steam  pipe  connecting  with  boiler  is 
long,  it  should  be  of  larger  size  than  the  inspirator  connections,  and 
if  the  pipe  is  horizontal,  pitch  it  so  as  to  return  condensation  back 
to  boiler. 

If  the  suction  is  filled  with  hot  water  from  the  same  cause,  it  may 
be  remedied  in  two  ways.  Cool  the  inspirator  and  suction  with  cold 
water,  or  else  pump  the  water  out  by  letting  the  steam  on  and  off 
suddenly  at  the  starting  valve  of  the  instrument,  until  the  hot  water 
has  been  disposed  of. 

If  the  inspirator  does  not  lift  water  well  the  difficulty  will  nearly 
always  be  found  with  the  suction,  which  must  be  absolutely  tight  to 


150         Management  and  Care  of  Machinery. 

secure  good  results.  The  lift  should  not  be  out  of  proportion  to  the 
steam  pressure,  the  overflow  should  be  wide  open  and  not  choked  by 
being  piped  too  small.  The  steam  and  air  should  be  given  free 
vent  at  the  overflow  to  raise  the  water.  Sometimes  when  the  suction 
is  very  hot,  the  water  becomes  very  much  heated  by  the  time  it 
reaches  the  inspirator,  and  it  will  not  condense  the  steam;  the  water 
will  come  up  into  the  inspirator,  but  will  not  pass  through  the  jet. 
The  simplest  way  to  overcome  this  trouble  is  to  shut  off  the  steam 
and  let  the  water  down.  This  will  cool  the  inspirator  and  suction 
and  you  can  then  let  on  the  steam  again  and  get  the  water  without 
difficulty.  If,  after  the  water  is  got,  it  will  not  penetrate  to  the 
boiler,  the  cause  is  often  due  to  "starving  "  the  inspirator,  not  giving 
it  water  enough.  It  is  caused  by  having  the  suction  too  small,  so 
that  the  "  lifter  "  does  not  supply  the  "  forcer  "  with  water  enough  to 
condense  the  steam  on  the  forcer  side,  hence  the  inspirator  refuses 
to  work.  Sometimes,  owing  to  a  leaky  steam  valve,  the  first  water 
that  comes  is  very  hot,  and  then  the  forcer  cannot  take  care  of  it,  as 
it  will  not  condense  the  steam.  When  this  is  the  trouble,  let  the 
water  run  out  at  the  overflow  until  it  becomes  cooler,  then  the  forcer 
will  take  it  and  send  it  to  the  boiler.  See  that  the  check  valve  in  the 
delivery  pipe  to  boiler  is  not  stuck  down,  and  that  it  has  enough 
play  not  to  choke  the  delivery.  This  pipe  should  be  as  large  as  the 
inspirator  connections.  A  leaky  suction  will  also  prevent  the  water 
going  to  the  boiler  when  the  forcer  valve  is  opened  and  the  final 
overflow  closed. 

BLOWING  OFF  OR  BLOWING  DOWN. — Boilers  should  never  be 
blown  out  while  hot,  as  the  plates  and  tubes  retain  sufficient  heat  to 
bake  the  deposits  into  a  hard  scale  that  becomes  firmly  attached  to 
their  surface.  The  boiler  should  always  be  allowed  to  cool  down 
before  the  water  is  run  out;  the  deposit  will  then  be  quite  soft,  and 
can  be  washed  off  with  a  hose.  Many  engineers  suppose  that  blow- 
ing out  under  pressure  tends  to  force  out  these  deposits  from  the 
boiler,  but  experience  has  shown  this  to  be  a  mistake. 

BANKING  FIRES. — During  stoppages  of  some  duration,  the  fires  are 
"banked  "  to  preserve  them  for  ready  use  without  consuming  fuel. 


Management  and  Care  of  Machinery.          151 

They  are  simply  smothered  partially  with  wet  slack  and  ashes,  the 
damper  is  closed,  furnace  door  opened  and  smoke-box  door  opened. 
A  little  attendance  to  the  draft  will  keep  the  fires  at  a  standstill.  If 
steam  begins  to  blow  off,  turn  on  cold  feed. 

To  REMOVE  SEDIMENT  AND  DEPOSIT. — The  handholes  should  be 
frequently  removed  and  all  incrustation  and  dirt  cleared  out.  Plates 
exposed  to  the  fire  should  be  kept  clean,  also  the  tubes,  flues  and 
connections.  If  the  tube  plates  and  tubes  are  heavily  coated  with 
scale,  the  slice  bar  and  hammer  must  be  brought  into  use.  The 
scale  can  be  loosened  by  injecting  i^oz.  of  muriate  of  ammonia 
twice  a  week,  which  will  materially  assist.  On  no  account  should 
the  boiler  be  heated  and  then  filled  with  cold  water  with  the  object 
of  cracking  the  scale  off  through  sudden  contraction  of  the  metal. 
Scale  should  not  be  allowed  to  accumulate  to  a  greater  thickness 
than  that  of  a  sheet  of  writing  paper.  The  tubes  are  swept  out  by 
wire  brushes,  the  soot  being  moistened  as  it  comes  out.  Or  they 
may  be  blown  out  by  a  jet  of  steam  from  a  strong  hose  with  a 
nozzle. 

Internal  or  external  corrosion  should  be  prevented.  If  any 
pitting  is  observed  inside,  a  coating  of  Portland  cement  mixed  with 
litharge  and  linseed  oil  should.be  applied  as  a  protection  to  the  iron. 
External  corrosion  will  most  frequently  start  in  places  where  the 
boiler  is  not  readily  accessible.  Periodical  inspection  with  •  painting 
is  the  only  preventive. 

SPLIT  TUBES. — Should  a  tube  start  leaking  when  under  steam,  it 
must  be  plugged.  Wood  plugs  can  be  driven  in  front  and  beyond 
the  leak.  They  will  swell  tight  and  withstand  considerable  pressure, 
but  may  be  blown  out,  when  the  fires  will  be  quenched  and  the  steam 
escape,  which  is  often  attended  by  serious  results  to  those  in  the 
stoke  hole.  Regular  tube  stoppers  should  always  be  on  hand.  They 
consist  of  a  rod  as  long  as  the  tube,  with  washers  and  nuts  at  each 
end.  The  rod  is  pointed  through  the  tube  and  the  nuts  set  up 
This  may  involve  drawing  the  fires  and  cooling  down,  according  to 
the  style  of  boiler.  Canvas  washers  steeped  in  red  lead  are 
introduced  under  the  iron  washers  to  make  a  tight  job. 


152          Management  and  Care  of  Machinery. 

BLISTERS. — When  a  blister  appears,  there  must  be  no  delay  in 
having  it  carefully  examined  and  patched. 

GENERAL  CARE.— In  very  shoal  water  slow  down  engine  and  feed 
pump  sopas  not  to  suck  grit  from  the  bottom.  A  little  of  it  under 
the  valves  of  the  pump  will  prevent  its  proper  working.  Try  the 
pump  occasionally  by  the  water  or  pet  cocks  to  see  that  it  is  acting. 
If  it  can  be  done,  stop  the  feed  until  deeper  water  is  reached. 
Keep  an  eye  on  water  cocks  and  glass  gauge  and  try  them  frequently 
to  be  certain  of  their  free  working.  Keep  the  boiler  dry  when  not 
in  use  by  burning  a  few  sticks  of  wood  in  the  furnace,  but  not 
enough  to  heat  up  the  shell.  In  open  launches,  a  hood  should  be 
provided  when  the  launch  is  not  running. 

WHEN  LAID  UP. — Dry  the  boiler,  take  off  manhole  covers, 
remove  safety  valve  and  cover  the  smokestack.  Whitewash  inside 
after  cleaning.  Uncouple  valves  and  plug  pipes  with  wood  steeped 
in  tallow  and  whitelead.  Allow  no  water  to  remain  in  the  elbows. 
Store  away  all  attachments  and  take  a  look  at  the  boiler  occasionally, 
so  that  no  water  may  collect  and  cause  oxidation. 

GETTING  UNDERWAY. — See  that  all  the  manholes  and  handhole 
plates  are  fully  screwed  up  over  the  packing  grummets  and  open  the 
blow-off  cocks,  allowing  the  water  to  fun  up  as  high  as  it  will,  unless 
it  is  proposed  to  fill  up  with  fresh  water  from  a  hose  on  the  dock. 
Meanwhile  get  the  fires  ready  and  start  when  the  boiler  has  been 
pumped  up  by  hand  to  the  level  required.  Blow-offs  are  to  be 
closed  after  running  up  the  water,  and  the  feed  pump  connected  for 
working  by  steam  after  boiler  is  full,  the  suction  opened  and  the 
check  valve  to  suit  as  well  as  intermediate  valves  in  the  feed  pipe. 
Injection  and  outboard  delivery  must  be  opened  ready  for  the  con- 
denser to  operate. 

Open  the  stop  valve  slowly  when  steam  has  been  raised.  Then 
open  the  throttle  valve  partly  and  the  blow-through  valves  and  drain 
cocks  on  the  engine.  Allow  the  steam  to  drive  the  water  and 
air  from  the  steam  chests,  cylinders  and  passages,  until  steam  alone 
issues  from  the  drain  cocks.  Close  the  blow-through  valves,  and 
the  steam  having  found  its  way  into  the  condenser,  will  be  precipi- 


Management  and  Care  of  Machinery.          153 

tated  by  the  cold  injection  water  in  the  pipes  and  form  a  partial 
vacuum.  Then  throw  the  valve  gear  partly  into  action  and  start  the 
engine  slowly,  being  sure  that  there  is  nothing  to  foul  the  screw. 
The  links  may  have  to  be  thrown  back  full  distance  in  some  engines 
to  give  a  good  supply  of  steam  to  start  the  machinery  from  rest. 
But  as  soon  as  started,  the  supply  should  be  checked  by  the  throttle, 
which  can  then  be  gradually  opened  wide  as  the  vessel  moves  away. 
All  the  machinery  will  then  be  in  regular  action.  The  circulating 
pump  is  forcing  cold  injection  through  the  condenser  pipes  and  the 
air  pump  is  drawing  off  the  condensed  steam  to  the  hot-well  or  tank 
from  which  the  feed  pump  returns  it  to  the  boiler,  if  operated  from 
the  main  engine,  or  else  must  be  given  steam  independently  to  suit. 
The  valves  can  be  regulated  by  watching  the  glass  water  gauge. 

In  compound  engines,  a  starting  valve  is  placed  on  a  connection 
between  the  steam  chest  of  the  high-pressure  cylinder  and  the  low- 
pressure  cylinder,  so  that  high  steam  may  be  admitted  into  the  latter 
to  assist  in  starting. 

ATTENDANCE  WHILE  RUNNING. — See  that  the  oil  cups  are  full 
and  wicks  in  order,  and  attend  those  of  the  cylinders,  by  closing  the 
upper  and  opening  the  lower  cock  on  the  vacuum  side  of  the  piston. 
Watch  the  bearings  that  they  may  not  heat.  If  this  is  found  to  be 
the  case,  slow  down  and  turn  on  cold  water  to  cool  them.  The 
stream  should  be  played  over  the  shaft  and  not  over  the  brasses,  as 
the  latter  are  liable  to  crack  or  scale  upon  sudden  cooling.  A  com- 
mon cause  of  hot  bearings  is  carelessness  when  polishing  the  engines 
with  fine  emery  paper,  as  grit  is  very  liable  to  work  its  way  into  the 
bearings. 

In  a  seaway,  the  throttle  requires  a  hand  stationed  to  manipulate 
the  valve  so  as  to  prevent  violent  "racing,"  unless  an.  efficient 
governor  is  attached.  Pumps  and  valves  need  attention  after  start- 
ing until  they  perform  their  functions  as  required.  Steam  and  water 
gauge  need  constant  inspection. 

THUMPING. — Water  in  the  cylinders,  loose  bearings,  loose  piston 
head,  hot  bearings,  too  little  cushioning,  slack  cotters  and  pins,  or 
loose  valve  gear,  will  be  indicated  by  various  noises  which  the 
engineer  soon  learns  to  distinguish. 


154         Management  and  Care  of  Machinery. 

LAYING  UP. — Pick  out  the  packing  from  stuffing  boxes  and  plug 
up  the  oil  holes  and  oil  feeders  with  tallow  or  plugs,  and  cover  up 
the  bearings  to  keep  out  dirt.  Clean  down  the  engines  and  cover 
the  polished  parts  with  white  lead  and  tallow.  Turn  or  move  the 
engines  once  in  a  while  to  prevent  corrosion,  and  keep  pipes,  valves 
and  elbows  free  from  water. 


X. 


THE     PRINCIPAL     TYPES     OF     YACHT 
MACHINERY. 

THE    PERKINS    HIGH    PRESSURE    SYSTEM. 

A  LTHOUGH  the  economy  attained  by  the  Perkins  boiler  and 
Jr\.  engine  has  of  late  been  equalled  in  some  cases,  the  system 
still  stands  at  the  head  of  modern  practice  so  far  as  high  pressure 
and  extreme  expansion  of  steam  is  concerned.  The  apparent  failure 
of  the  Perkins  system  to  reach  such  results  as  might  be  expected 
from  steam  at  360  and  400  Ibs.  pressure,  is  due  to  details  in  design 
of  engines  which  interfere  with  the  full  realization  in  practice  of  the 
possibilities  of  the  system.  Many  apparently  insurmountable  diffi- 
culties in  the  way  of  employing  great  pressures  have  been  already 
successfully  overcome,  and  if  further  improvements  keep  pace  with 
the  experience  gained  from  the  actual  application  of  the  system  to 
marine  purposes,  there  is  reason  to  believe  that  the  fuel  consumption 
will  be  brought  dowrn  to  i  Ib.  of  coal  per  horse  power  per  hour. 

All  objection  to  generating  high  pressures  in  a  steam  boiler  have 
been  met  in  the  pipe  arrangement  illustrated  in  the  chapter  on 
Boilers.  It  combines  a  maximum  of  strength  and  safety,  which  can 
be  supplied  far  beyond  the  critical  necessities  of  each  case.  By  the 
use  of  perfectly  fresh  or  distilled  water,  incrustation  and  injury  from 
acids  is  avoided,  so  that  small  tubes  can  be  used  without  trouble  or 
damage.  These  are  arranged  horizontally,  with  an  internal  diameter 


156  Principal  Types  of  Yacht  Machinery. 

of  2^  in.  and  3  in  outside,  except  the  steam  drum  on  top  which  is 
4  in.  internal  and  5%  in.  external  diameter.  Th'e  horizontal  tubes 
are  welded  up  at  each  end  ^  in.  thick  and  all  are  connected  by 


FIG.  57. — THE  CONDENSER  AND  STILL. 

small  vertical  joints  of  J/%  in.  internal  and  i-fc  in.  external  diameter. 
The  fire  box  is  built  up  of  tubes  in  rectangular  form,  connected  to 
one  another  by  numerous  vertical  joints  as  shown  in  the  cuts.  The 
boiler  is  inclosed  in  a  double  casing  of  sheet  iron,  the  space  between 
being  filled  up  with  vegetable  black  or  non-conducting  substance. 


Principal  Types  of  Yacht  Machinery.  1 5  7 

Each  tube  is  proved  by  hydraulic  pressure  to  4,000  Ibs.  and  the 
boiler  as  a  whole  to  2,000  Ibs.  without  showing  leakage  in  several 
hours  test. 

The  boiler  can  be  worked  with  great  regularity,  without  priming 
and  with  steam  free  from  moisture.  Repairs  are  easily  made,  for 
damage  can  only  be  local.  If  the  feed  gives  out,  the  only  chance  of 
serious  injury  to  the  tubes  can  be  prevented  by  dampening  or  draw- 
ing fires  quickly  as  in  any  other  boiler,  while  the  disastrous  results 
from  explosion  are  reduced  to  a  minimum  from  the  small  body  of 
water  and  steam  carried. 

Distilled  water  is  however  a  necessity  to  the  preservation  of  the 
internal  surfaces  of  the  boiler.  The  feed  water  is  used  over  and 
over  again  without  admixture  of  sea  water,  by  designing  all  parts  of 
the  machinery  to  be  practically  water-tight.  The  leakage  is  so  small 
that  10  gallons  per  100  Indicated  H.  P.  per  24  hours  will  supply  the 
waste.  An  actual  test  made  upon  engines  indicating  250  H.  P.,  with 
steam  from  the  boiler  at  250  Ibs.,  developed  no  loss  of  water  during 
thirteen  days  continuous  running. 

The  exhaust  steam  from  the  engine  is  passed  into  a  vertical  sur- 
face condenser,  the  tubes  of  which  are  absolutely  tight,  the  injection 
passing  through  the  tubes  and  the  exhaust  steam  surrounding  them. 
The  tubes  are  ^6  in.  internal  and  i  ^  external  diameter  and  welded 
up  at  the  top  end  and  securely  fixed  in  a  bottom  tube  plate.  Inter- 
nal tubes  cause  the  water  to  circulate  to  the  extreme  ends  as  shown 
by  the  arrows  in  the  cut.  The  small  still  is  used  to  produce  fresh 
water  as  a  supply  for  such  waste  as  may  take  place.  Steam  blowing 
off  at  the  safety  valve  is  returned  to  the  condenser,  and  there  may  be 
a  margin  of  roolbs.  per  sq.  in.  between  the  load  on  the  safety  valve 
and  the  pressure  required  to  work  the*  engines.  The  tubes  of  a 
boiler  built  in  1861  were  cut  in  1874  and  submitted  to  official 
examination  by  the  British  Admiralty  Boiler  Committee.  The  tubes 
were  in  an  excellent  state  of  preservation  after  thirteen  years  use, 
with  the  longitudinal  lines  in  them  as  sharp  and  well  defined  as  in 
new  ones. 

The  use  of  high  pressures  involved  a  remodeling  of  the  engine  as 
shown  in  the  sectional  diagram. 


158  Principal  Types  of  Yacht  Machinery. 

There  are  three  cylinders,  the  first,  A,  is  single-acting,  and  the 
second,  B,  likewise,  having  four  times  the  capacity  of  the  first,  the 
pistons  of  both  operating  upon  the  same  piston  rod.  The  third 
cylinder,  C,  is  double-acting,  four  times  the  capacity  of  the  second, 
the  piston  rod  being  connected  to  a  crank  at  right  angles  with  the 
high-pressure  crank.  Lubricating  the  first  cylinder  and  the  use  of 
glands  and  packing  were  out  of  question  with  such  high  pressure, 
hence  the  novel  arrangement  of  the  initial  cylinder,  whereby  glands 


FIG.  58. — SECTION  OF  PERKINS  ENGINE  THROUGH  CYLINDERS. 


are  dispensed  with.  The  steam  is  cut  off  at  half  stroke  in  A  and 
exhausts  under  piston  B  for  the  up  stroke.  The  temperature  is  by 
that  time  so  much  reduced  that  no  serious  difficulty  is  experienced 
in  the  use  of  the  gland  and  packing.  From  the  bottom  of  second 
cylinder  B,  the  steam  escapes  into  the  top  of  the  same,  which  serves 
as  the  intermediate  chamber  in  connection  with  the  valve  chest  of 
the  third  cylinder  C.  The  latter  is  arranged  to  cut  off  at  one- 
quarter  stroke  and  exhausts  into  the  condenser,  the  total  expansion 
being  2X4X4  =  32.  All  cylinders  are  steam- jacketed  with  coils, 
the  condensed  water  of  which  is  returned  to  the  hot-well.  The 
cylinders  and  valve  boxes  are  also  surrounded  by  a  double  sheet 


Principal  Types  of  Yacht  Machinery.  159 

iron  casing,  filled  with  some  non-conductor.  The  ordinary  mode  of 
packing  the  pistons  and  depending  upon  lubrication  is  superseded 
by  the  introduction  of  piston  rings  made  of  five  parts  of  tin  and 
fifteen  of  copper.  Extensive  practice  in  this  and  other  engines  has 
now  established  the  perfect  feasibility  of  the  plan. 

Thornycroft  high-speed  launches  have  been  put  through  their  trial 
trips  of  two  hours  duration,  making  430  revolutions  per  minute, 
without  the  use  of  oil  or  grease,  depending  upon  the  rings  of  alloy 
only.  The  rings  have  been  in  use  for  nearly  three  years  in 
stationary  engines  without  lubrication  of  any  sort.  They  have  been 
a  success  on  seagoing  steamers  running  10,000  miles,  and  showing 
cylinders  smoothed  up  beautifully  and  giving  no  trouble  thereafter. 
The  steam  yacht  Anthracite  made  her  transatlantic  voyage  without 
any  trouble  on  the  score  of  piston  lubrication. 

The  Perkins  engine  and  boiler  is  specially  adapted  to  yachting 
purposes.  The  machinery  is  compact  and  takes  up  little  space 
longitudinally.  The  boiler  cannot  burst  with  violence.  It  does  not 
prime  in  a  seaway  and  there  is  no  noisy  blowing  off  of  steam. 
Engines  can  be  stopped  upon  a  moment's  notice  without  risk  of 
running  up  steam  to  dangerous  pressure,  as  the  tubes  can  be  cooled 
to  suit  in  a  moment  by  attending  the  furnace  door  and  damper. 
There  is  no  smell  and  grease  as  no  lubricants  are  used  in  the 
cylinders.  The  engine  room  can  be  kept  as  neat  as  the  cabin. 

Experiments  made  upon  the  steamer  Anthracite  by  Mr.  F.  J. 
Bramwell,  before  her  departure  fqr  America,  gave  an  economic 
result  of  i.83lbs.  of  coal  per  I.  H.  P.  per  hour.  The  results  obtained 
by  dock  trial  at  the  Brooklyn  Navy  Yard  were  not  as  favorable  as 
shown  below,  the  consumption  being  2.7lbs.  But  this  difference  is 
fully  acounted  for  in  the  official  report  made  to  the  U.  S.  Navy  De- 
partment by  Chief  Engineers  Loring,  Ayers  and  Magee,  appointed 
to  make  the  official  test. 

The  difference  of  36.88  per  cent,  in  the  two  results  is  partly 
attributed  to  the  use  of  inferior  coal  in  the  American  trial,  the 
English  test  having  been  made  with  standard  Nixon-  Navigation 
coal  used  in  the  measured  mile  runs  of  the  British  Admiralty,  having 
only  5  per  cent,  of  loose  white  ash  against  17.6  per  cent,  of  ash  and 


160          Principal  Types  of  Yacht  Machinery. 

clinker  in  the  American  Cumberland  coal.  Messrs.  Loring,  Ayers 
and  Magee  report  that  after  allowing  for  this,  there  remained  a 
difference  of  17.64  per  cent,  superiority  in  Mr.  Bramwell's  trial  to  be 
accounted  for,  and  this  they  attribute  to  their  carrying  the  water  at 
too  high  a  level,  losing  the  advantage  of  superheated  steam.  The 
piston  speed  was  greater  in  the  Bramwell  experiment  with  less 
cylinder  condensation  in  consequence,  the  difference  being  due  to 
making  the  English  trial  under  way  and  the  American  trial  at  the 
dock.  It  has  also  been  stated  that  the  first  cylinder  was  not 
properly  steam  jacketed  in  the  American  trial,  which  seems  probable 
from  the  fact  that  the  condensation  was  found  to  be  34.99  per  cent, 
by  Mr.  Bramwell  against  56.22  by  the  U.  S.  Navy  Committee. 
Calculations  were  made  to  discover  whether  the  greater  condensation 
in  the  American  trial  would  represent  the  excess  in  fuel  consumed 
and  the  committee  report  that  such  was  the  case.  Furthermore,  the 
engines  were  shown  to  be  faulty  in  some  details  of  construction, 
.notably  in  the  mode  of  steam  jacketing  and  in  the  excessive 
clearances  and  steam  passages,  being  from  two  to  four  times  greater 
than  required.  This  could  be  eliminated  by  a  revision  of  the  details 
of  design,  promising  correspondingly  greater  economy  in  fuel  con- 
sumption. 

i  The  Anthracite  was  built  in  1878  by  Schlesinger,  Davis  &  Co.,  of 
Newcastle,  and  classed  Ai,  n  years,  at  Lloyds.  She  has  an  iron 
.hull,  with  four  bulkheads,  registers  69.30  tons  gross  and  30  tons  net. 
Her  length  on  deck  is  86ft.  4  in.,  beam  i6ft.,  and  depth  of  hold 
.10  ft.  She  left  Erith  on  the  Thames,  England,  May  29,  1880,  and 
.arrived  at  New  York  July  2,  after  touching  at  Falmouth  and  St. 
Johns,  N.  F.  The  passage  from  land  to  land  was  made  in  18  days, 
the  whole  distance  under  steam  only,  through  heavy  weather  and 
rough  sea.  The  engines  have  already  been  described.  She  used 
436  gallons  of  distilled  water  to  supply  the  waste  during  her  trip 
across.  Cylinders  were  7^,  15}!  and  22||in.  bore,  with  15  in. 
stroke.  Diameter  of  piston  rods  to  be  deducted  from  the  areas  of 
.second  and'third  cylinders,  is  2%  in. 

The  valve  motion  is  derived  from   eccentrics,  the   low-pressure 
cylinder  having  an  ordinary  slide  valve  with  an  expansion  valve  on 


FIG.  59, — ENGINES  OF  S,  S.  ANTHRACITE.    FRONT  ELEVATION. 

[161! 


FIG.  60. — ENGINES  OF  S,  S,  ANTHRACITE,     SIDE  ELEVATION. 


Principal  Types  of  Yacht  Machinery.  163 

its  back  worked  by  the  prolongation  upward  of  the  circulating  pump 
rod.  Steam  is  cut  off  in  the  high-pressure  cylinder  by  three  lifting 
double-beat  valves,  the  upper  faces  being  divided  into  sections.  The 
surface  condenser  is  supplied  with  galvanized  wrought  iron  tubes  of 
422  sq.  ft.  surface. 

The  circulating  pump  is  n^in.  diameter,  worked  by  a  beam  off 
the  low-pressure  piston  rod,  the  air  pump,  of  like  diameter,  being 
actuated  by  a  similar  beam  off  the  intermediate  cylinder  piston  rod. 
The  two  feed  pumps,  of  2  in.  diameter,  and  the  two  bilge  pumps,  of 
3  in.  diameter,  are  actuated  from  the  crossheads  of  the  circulating 
and  air  pumps.  The  engine  is  reversed  by  screw  hand  wheel  and 
link  gear. 

The  boiler  has  15  sq.  ft.  of  grate  area  and  633  sq.ft.  of  heating  sur- 
face, the  pressure  ranging  from  300  to  500  Ibs. 

From  the  U.  S.  Government  report  of  the  Anthracite's  trial,  tied 
up  to  the  dock  at  the  Brooklyn  Navy  Yard,  the  following  data  are 
obtained,  consumption  of  coal  having  already  been  considered: 

Pounds  of  coal  consumed  per  hour  per  indicated  horse  power 2.7115 

Total  quantity  of  Cumberland  semi-bituminous  coal  consumed,  in  pounds         4,400 

Total  pounds  of  refuse  in  ash  and  clinker 776 

Total  pounds  of  combustible  consumed 3,624 

Total  pounds  of  feed  water  pumped  into  the  boiler 35, 114 

Total  double  strokes  of  the  pistons 148, 154 

Steam  pressure  in  the  boiler,  in  pounds,  above  the  atmosphere 316,50 

Steam  pressure  in  the  cylinder,  in  pounds,  above  the  atmosphere 210.54 

Throttle  wide  open 

(In  none  of  the   cylinders  was  the  steam  cushioned,  nor  was  there 

steam  or  exhaust  lead.) 

Vacuum  in  condenser,  in  inches  of  mercury 26.75 

Back  pressure  in  condenser,  in  pounds,  above  zero 1. 6066 

Temperature,  in  degrees  Fahr.,  of  feed  water 120.5 

Temperature,  in  degrees,  of  steam  in  the  boiler,  saturated 420.0 

Pounds  of  coal  consumed  per  hour 183.5883 

Pounds  of  coal  consumed  per  hour  per  square  foot  of  grate 11.9867 

Mean  back  pressure  against  the  piston  of  third  cylinder,  in  pounds 4.21 

Indicated  horse  power  of  1st  cylinder 20.4308 

2d        "       7.8290 

3d        "        39-4483 

Aggregate  indicated  horse  power  for  all  three  cylinders 67.7081 

Total  horse  power  developed  in  three  cylinders 80. 1525 


1 64          Principal  Types  of  Yacht  Machinery. 

Pounds  of  feed  water  consumed  per  hour  per  indicated  horse  power 21.63875 

Pounds  of  steam  condensed  in  the  first,  second  and  third  cylinders,  to 
furnish  the  heat  transmitted  into  the  total  horse  power  developed  in 

those  cylinders,  by  the  expanded  steam  alone 167.0720 

Pounds  of  water  vaporized  from  212°  by  one  pound  of  coal 9.2671 

Duration  of  trial  in  hours 24 

Total  weight  of  machinery,  engines,  boiler,  screw  shaft,  propeller  and  all 
fittings,  in  tons  .... 25 

THE   HERRESHOFF    SYSTEM. 

The  coil  boiler,  upon  which  the  Herreshoff  system  rests,  has  all 
the  advantages  of  "the  pipe  arrangement  described  in  the  Perkins 
system,  and  in  addition  the  very  material  one  of  light  weight  in 
comparison  to  the  power.  This  makes  the  coil  especially  suited  to 
high  speed  yachts,  as  the  saving  in  weight  enables  refinement  of 
form  in  hull  beyond  the  displacement  which  is  a  necessity  for 
heavier  steam  generators.  The  coil  boiler  is  also  particularly  well 
adapted  for  launches  and  cutters,  owing  to  the  quick  raising  of  steam 
and  the  possibility  of  hoisting  such  boats  to  the  davits  of  a  large 
steam  yacht,  without  removing  the  machinery  and  without  undue 
strain.  An  extensive  report  concerning  the  Herreshoff  method  was 
made  to  the  Bureau  of  Steam  Engineering,  U.  S.  Navy  Department, 
in  1 88 1.  The  experiments  were  carried  out  upon  the  steam  yacht 
Leila  by  Chief  Engineers  B.  F.  Isherwood,  Theo.  Zeller  and  Geo. 
W.  Magee.  It  is  worth  noting  that  this  was  done  at  the  invitation 
of  the  Herreshoff  Manufacturing  Co.,  of  Bristol,  R.  I.,  and  that  they 
freely  undertook  the  entire  expense  attendant  upon  the  trials.  These 
have  since  been  frequently  referred  to  by  the  engineering  world  in 
making  comparisons  with  other  machinery,  and  the  liberality  of  the 
manufacturers  stands  as  an  example  which  other  builders  of  special 
systems  might  follow  with  benefit  to  all  concerned.  From  the  offi- 
cial report  much  of  the  following  description  is  extracted.  It  should 
be  added  that  their  practice  in  building  compound  engines  has  been 
of  late  supplemented  by  new  patterns  of  triple  expansion  engines, 
for  which  the  Herreshoff  system  is  equally  well  adapted. 

The  steam  yacht  Leila,  as  an  example,  is  of  composite  construc- 
tion, the  frame  being  of  angle  iron  planked  with  Southern  pine  and 


Principal  Types  of  Yacht  Machinery.  165 

sheathed  with  copper;  the  stem  and  sternpost  are  of  wood.  The 
waterlines  of  the  hull  are  excessively  sharp  and  the  angle  of  its 
dead  rise  proportionally  great. 

The  draft  of  water  of  the  hull  proper  at  the  stern  was  so  small 
that  the  screw  had  partly  to  descend  below  the  bottom  of  the  keel  in 
order  to  be  wholly  immersed;  this  required  the  addition  of  a  skeg  at 
the  stern  and  below  the  keel,  for  the  purpose  of  protecting  the  screw 
and  of  supporting  the  metallic  shoe  which  extends  horizontally  be- 
neath it.  The  aftermost  end  of  this  shoe  sustains  the  lower  pintle 
of  the  rudder;  the  latter  is  of  copper  and  counterbalanced  with  the 
axis  at  one-fourth  of  its  breadth  from  the  forward  edge. 

The  skeg  is  a  right-angled  triangle  of  wood,  15^  in.  deep  below 
the  bottom  of  the  keel,  at  the  after  side  of  the  sternpost,  and  60  in. 
long  upon  the  bottom  of  the  keel  from  the  after  side  of  the  stern- 
post;  its  breadth  is  7  in. 

The  following  are  the  principal  dimensions  and  proportions  of  the 
hull: 

Extreme  length  on  top  of  deck 100  ft. 

Length  on  waterline  from  forward  edge  of  stem  to  after  side  of  stern- 
post 95  ft.  5  in. 

Extreme  breadth  on  top  of  deck 15  ft.  4  in. 

Extreme  breadth  on  waterline II  ft.  9  in. 

Depth  of  hull  amidship  from  lower  edge  of  rabbet  of  keel  to  top  of 

deck  beams 5  ft.  loin. 

Depth  at  stern  from  waterline  to  lower  edge  of  rabbet  of  keel 3  ft.  I  ^  in. 

Depth  of  keel  aft,  below  lower  edge  of  its  rabbet 8^  in. 

Siding  of  keel 7  in. 

Distance  from  the  forward  edge  of  the  stem  to  the  greatest  immersed 

transverse  section 54  ft.  6  in. 

Area  of  the  waterline 699.5  sq.  ft. 

Area  of  the  greatest  immersed  transverse  section,  including  projected 

areas  of  keel  and  skeg 2O.i2sq.  ft. 

Displacement  (35  cu.  ft.  per  ton) 37-27  tons. 

Aggregate  area  of  wetted  surfaces  of  hull,  keel  and  skeg 935-5  sq.  ft. 

Angle  of  dead  rise  at  greatest  immersed  transverse  section 21^  deg. 

Half  angle  of  bow  on  waterline 8^  deg. 

Half  angle  of  stern  on  waterline 14  deg. 

Ratio  of  the  length  to  the  breadth  on  waterline S.  1206 

Ratio  of  waterline  plane  to  circumscribing  parallelogram 0.6239 

Ratio  of  the  greatest  immersed  transverse  section  to  its  circumscribing 

parallelogram .o.  5624 


1 66  Principal  Types  of  Yacht  Machinery. 

Ratio  of  the  displacement  above  lower  edge  of  rabbet  of  keel  to  its  cir- 
cumscribing parallelopipedon 0.3721 

Distance  between  centers  of  angle-iron  frames I  ft.  3  in. 

Angle-iron  frames,  molded i/^  in. 

Angle-iron  frames,  sided 2^  in. 

Thickness  of  iron  of  angle-iron  frames ^  in. 

Deck  beams,  molded 2  in. 

Deck  beams,  sided 3/4  in> 

Thickness  of  wooden  stem 6  in. 

Thickness  of  wooden  sternpost 7  in. 

Thickness  of  bottom  and  side  planking I  ^  in. 

Thickness  of  deck  planking i-fo  in. 

The  Leila  has  one  boiler  with  single  circular  furnace,  around 
and  over  which  the  continuous  pipe  of  wrought  iron  composing  the 
heating  surface  is  coiled  spirally  and  symmetrically  into  two  con- 
centric coils,  one  coil  being  immediately  on  the  outside  of  the  other 
so  as  to  surround  it.  This  pipe  contains  the  water  to  be  evaporized, 
and  the  hot  gases  of  combustion  act  on  its  exterior,  enveloping 
every  part  of  it  from  one  end  to  the  other.  The  grate,  circular  in 
plan,  is  inclosed  by  a  circular  wall  of  brick  masonry,  on  the  top  of 
which  the  double  coil  rests,  and  the  latter  is  surrounded  by  two 
concentric  casings  of  sheet-iron,  with  an  air  space  between.  The 
whole  of  the  gases  of  combustion  pass  between  the  spirals  from  the 
inside  to  the  outside  of  the  two  coils  into  the  space  between  the 
latter  and  the  casing,  and  from  this  space  these  gases  ascend  the 
chimney.  The  feed  water  enters  the  inside  coil  at  the  extreme 
upper  end,  whence  it  flows  partly  by  gravity,  but  mainly  by  the 
action  of  the  feed  pump,  down  to  the  extreme  lower  end  of  this 
coil  ;  thence  into  the  extreme  lower  end  of  the  outside  coil,  up 
which  it  ascends  to  the  extreme  upper  end,  being  converted  in  its 
progress  into  steam.  If  the  supply  of  feed  water  relatively  to  the 
heat  of  the  furnace  be  such  that  the  former  is  entirely  vaporized  by 
only  a  portion  of  the  heating  surface  in  the  coils,  then  the  remain- 
ing portion  of  that  surface  will  act  to  superheat  the  steam.  As  the 
latter  effect  should  be  avoided  on  account  of  the  injurious  action  of 
the  intense  direct  heat  of  the  furnace  on  the  iron  of  the  pipe  when 
unprotected  by  water,  recourse  is  had  to  a  forced  circulation  of  a 
superfluous  quantity  of  feed  water  by  means  of  a  circulating  pump, 


Principal  Types  of  Yacht  Machinery.  167 

which,  by  continually  drawing  this  superfluous  feed  water  from  the 
delivering  end  of  the  double  coil  and  forcing  it  into  the  receiving 
end,  keeps  both  coils  always  sufficiently  filled  with  water  to  prevent 
steam  superheating,  let  the  quantity  of  water  vaporized  be  what  it 
may.  The  feed  and  the  superfluous  feed  both  enter  simultaneously 
and  at  the  same  point.  The  mixed  water  and  steam  are  projected 
from  the  delivering  end  of  the  coil  pipe  into  the  "separator,"  which 
is  merely  a  closed  cylindrical  vessel  where  the  water,  by  its  greater 
gravity,  separates  from  the  steam  and  falls  to  the  bottom,  while  the 
steam  is  carried  off  from  the  top  by  a  pipe,  which,  after  winding 
spirally  two  and  five-eighths  times  around  the  upper  portion  of  the 
inside  coil,  appearing  like  an  extension  of  the  upper  portion  of  the 
outside  coil  on  which  it  rests,  passes  to  the  engine.  All  the  surface 
in  these  two  and  five-eighths  spirals  is  steam-superheating  surface, 
which,  ^being  exposed  to  the  gases  of  combustion  at  high  temper- 
ature, acts  very  efficiently  for  that  purpose.  The  water  collected  in 
the  "separator"  is  again  pumped  by  the  circulating  pump  into  the 
top  of  the  pipe  of  the  inside  coil.  The  "separator"  acts  both  as  a 
vessel  in  which  the  separation  of  the  water  and  steam  takes  place 
and  a  steam  drum  for  the  storage  of  steam,  at  approximately  con- 
stant pressure.  In  this  boiler  the  water  and  steam  occupy  exactly 
opposite  positions  to  what  they  do  in  ordinary  boilers,  the  water 
being  in  the  top  and  the  steam  in  the  bottom  of  the  coil. 

Upon  the  "separator"  are  placed  the  safety  valve, ' the  steam- 
pressure  gauge,  and  a  glass  water  gauge  for  showing  the  height  of 
the  water  in  the  lower  portion  of  the  "separator."  This  height  is 
the  water  level  to  be  carried,  and  its  maintenance  regulates  the 
quantity  of  superfluous  feed  water  to  be  pumped  in  by  the 
circulating  pump.  By  properly  proportioning  that  pump,  any 
amount  of  superfluous  feed  water  can  be  kept  in  circulation,  and  the 
current  forced  over  the  heating  surfaces  in  such  a  torrent  as  to  sweep 
off  the  steam  bubbles  as  fast  as  formed,  and  to  change  and  mix  the 
water  with  such  rapidity  as  to  obtain  the  maximum  heating  efficiency 
from  a  given  area  of  those  surfaces  in  a  given  time.  The  glass 
water  gauge  on  the  "separator"  answers  the  same  purpose  as  the 
gauge  cocks  on  boilers  of  the  usual  construction,  and  requires  to  be 


1 68  Principal  Types  of  Yacht  Machinery. 

as  closely  watched,  for  on  the  continuous  passage  through  the  coil 
pipe  of  an  excess  of  feed  water  over  what  is  vaporized  depends  the 
preservation  of  the  metal  from  burning. 

The  furnace  consists  of  a  circular  grate  5  ft.  and  9  in.  in  diameter, 
surrounded  by  a  circular  vertical  wall  of  fire  brick  laid  in  fire  clay. 
The  opening  for  the  ashpit  door  is  13  in.  wide  and  nin.  high. 
Opposite  the  door  is  another  opening  for  receiving  the  blast  from  a 
fan  blower. 

Upon  the  top  of  the  brick  wall  inclosing  the  furnace  rests  the 
double  coil  of  continuous  wrought  iron  pipe.  The  inner  coil  maybe 
conceived  to  be  wound  spirally  around  the  frusta  of  two  right  cones, 
one  super-imposed  upon  the  other,  and  having  their  axes  in  the 
same  vertical  line.  These  imaginary  frusta  form  the  inner  dimen- 
sions of  the  inside  coil.  The  lower  one  is  5  ft.  5  in.  in  diameter  at 
bottom,  4  ft.  8  in.  in  diameter  at  top,  and  4ft.  3  in.  in  height.  The 
upper  one  is  4ft.  8  in.  in  diameter  at  bottom,  i  ft.  4  in.  in  diameter  at 
top,  and  8  in.  in  height.  Above  these  two  frusta  the  pipe  forming 
the  inside  coil  is  extended  into  a  nearly  horizontal  spiral  of  6  ft.  10  in. 
in  extreme  diameter,  formed  of  eleven  and  a  half  circumvolutions, 
and  placed  as  low  as  the  upper  frustum  will  allow.  This  horizontal 
spiral,  situated  in  the  uptake  and  above  the  coils,  is  exposed  to  the 
hot  gases  of  combustion  just  before  they  enter  the  chimney,  and 
after  as  much  of  their  heat  as  possible  has  been  extracted  by  the 
coils  with  which  they  first  come  in  contact.  Consequently,  it  acts  as 
a  heater,  the  feed  water  and  circulating  water  being  delivered  into  it 
at  one  extremity,  forced  round  the  spirals  by  the  feed  and  circulat- 
ing pumps,  and  emerging  from  it  into  the  inside  coil  at  the  other 
extremity,  with  which  it  is  continuous. 

The  pipe  composing  the  horizontal  spiral  is  of  wrought-iron, 
lap-welded,  i  ^  in.  outside  diameter  and  i^in.  inside  diameter; 
thickness  of  metal  A  in.  The  exterior  surface  of  the  horizonal  spiral 
is  73. 63  sq.ft.,  its  interior  surface  is  58. 90 sq.  ft.,  and  its  content  is 
1.8401.  ft. 

The  inside,  coil,  starting  from  the  top,  is  composed  of  four  turns 
or  helical  spirals  of  wrought-iron  lap-welded  pipe,  i%  in.  outside 
diameter  and  1^/2  in.  inside  diameter,  thickness  of  metal,  A  in.;  five 


i  70  Principal  Types  of  Yacht  Machinery. 

spirals  of  2^6  in.  outside  diameter  and  2  in.  inside  diameter,  thick- 
ness of  metal,  A  in  ;  eight  and  a  half  spirals  of  2^3  in.  outside 
diameter  and  2^/2  in.  inside  diameter,  thickness  of  metal  iVin.;  and 
five  and  a  half  spirals  of  3^  in.  outside  diameter  and  3  in.  inside 
diameter,  thickness  of  metal  %  in.  The  four  spirals  of  i  ^6  in. 
outside  diameter  pipe  and  the  five  spirals  of  2^§  in.  outside  diameter 
pipe  form  the  top  of  the  furnace  and  are  in  close  contact,  so  that 
none  of  the  gases  of  combustion  can  pass  between  them.  The 
eight  and  a  half  spirals  of  2^  in.  outside  diameter  pipe  and  the 
five  and  a  half  spirals  of  3^  in.  outside  diameter  pipe  form  the 
sides  of  the  furnace,  and  are  separated  by  spaces  through  which 
all  the  gases  of  combustion  pass.  The  exterior  surface  of  the 
inside  coil  is  239.12  sq.  ft.,  the  interior  surface  is  204.98 sq.ft.,  and 
the  contents  10.93  cu-  ft- 

The  outside  coil,  continuous  with  the  inside  coil  and  connecting 
with  it  at  the  bottom,  is  composed  of  nine  and  three-fourths  spirals 
of  wrought-iron  lap-welded  pipe  3^2  in.  outside  diameter  and  3  in. 
inside  diameter,  thickness  of  metal  %  in.  The  space  between  the 
outside  coil  and  the  inside  coil  is  i  y%  in.  The  exterior  surface  of 
this  coil  is  172.26  sq.  ft.,  the  interior  surface  is  147.65  sq.  ft.,  and  the 
contents  9.23  cu.  ft. 

Total  water  heating  surface  of  the  boiler  is  485.02  sq.  ft.  exterior 
pipe  surface,  with  411.56  sq.  ft.  interior  surface,  and  contents  of  22.00 
cu.  ft. 

The  superheater  on  top  of  outside  coil  has  43.98  sq.  ft.  exterior 
surface,  37. 70 sq.ft.  interior  surface,  and  2.36  cu.  ft.  contents. 

All  the  gases  of  combustion,  after  passing  between  the  spirals  of 
the  two  coils  and  the  superheater,  impinge  on  the  inside  casing, 
which  has  thus  nearly  their  temperature. 

The  uptake  rests  upon  the  casings,  and  is  composed  like  them  of 
two  parallel  sheet  iron  plates  -iV  in.  thick,  with  a  ^  in.  intervening 
space  filled  with  mineral  wool.  The  form  of  the  uptake  is  a  frustum 
of  a  right  cone,  7  ft.  in  diameter  at  bottom,  2  ft.  in  diameter  at  top, 
and  7  in.  in  height. 

The  chimney  rests  upon  the  uptake,  and  is  2  ft.  in  diameter  and 
20  ft.  in  height  above  it. 


Principal  Types  of  Yacht  Machinery.  171 

The  "separator"  is  placed  by  the  side  of  the  boiler,  with  a  space 
of  7^  in.  between  them.  It  is  simply  a  hollow  cylinder  formed  of 
2/8  in.  thick  boiler  plate,  and  has  both  top  and  bottom  closed.  It 
receives  at  the  top  the  mingled  water  and  steam  from  the  top  or 
delivering  end  of  the  outside  coil,  which  i§  prolonged  into  the 
"  separator  "  for  about  one-third  the  height  of  the  latter.  In  the 
"  separator"  the  water  is  separated  from  the  steam  by  gravity  and 
falls  to  the  bottom,  while  the  steam  is  carried  off  from  the  top  of  the 
"  separator  "  by  the  superheating  coils  which  lead  it  to  the  engine. 
The  "separator"  is  thus  an  independent  but  essential  adjunct  of  the 
boiler,  intended  to  act  both  as  a  steam  reservoir  or  steam  drum  and 
as  a  water  trap.  The  top  is  fitted  with  a  safety  valve  of  the  usual 
construction,  and  the  bottom  is  fitted  with  a  blow-off  pipe  and  cock 
for  draining  the  "  separator  "  and  blowing  out  any  sediment  that 
may  collect  in  it.  On  the  side  of  the  lower  portion  of  the  "  separa- 
tor "  is  a  glass  water  gauge  of  the  usual  construction,  which  shows 
on  inspection  whether  there  is  an  excess  of  feed  water  passing  through 
the  coils  of  the  boiler;  the  proper  performance  of  the  boiler  requir- 
ing always  such  excess.  From  near  the  bottom  of  the  "separa- 
tor "  a  pipe  proceeds  to  the  circulating  pump,  which  continually 
removes  this  excess  of  feed  water  and  forces  it  back  into  the  boiler 
by  a  pipe  connecting  the  delivery  of  the  pump  with  the  receiving 
end  of  the  heater  coil. 

The  principal  dimensions  of  the  Leila's  boiler  are  summed  up  below: 

Diameter  of  the  boiler  to  outside  of  casing 84  in. 

Height  of  boiler  from  bottom  of  ashpit  to  top  of  uptake 99  in. 

Diameter  of  the  furnace 69  in. 

Area  of  the  grate  surface 25.9673  sq.  ft. 

Area  of  water-heating  surface  measured  on  outside  of  coil  pipe  . .  .485. 01723  sq.  ft. 
Area  of  steam  superheating  surface  measured  on  outside  of  coil 

pipe 43.9824  sq.  ft. 

Cross  area  of  chimney 3-J4i6 sq.  ft. 

Height  of  the  chimney  above  the  level  of  the  grate  bars 27  ft. 

Interior  diameter  of  the  "  separator  ' 14  in. 

Interior  height  of  the  ' '  separator     50  in. 

Total  steam  room  in  separator  and  superheater 6.0083  cu.  ft. 

Aggregate  contents  (water  and  steam)  of  the  heater   and  of  the 

inside  and  outside  coils 21.99793  cu.  ft. 


172  Principal  Types  of  Yacht  Machinery. 

Square  feet  of  water-heating  surface,  measured  on  outside  of  coil 

pipe,  per  square  foot  of  grate  surface i8..678o 

Square  feet  of  steam-superheating  surface,  measured  on  outside  of 

coil  pipe,  per  square  foot  of  grate  surface 1.6938 

Square  feet  of  grate  surface  per  square  foot  of  cross  area  of  chim- 
ney for  the  passage  of  the  gases  of  combustion 8.2656 

The  engines  of  the  Leila  are  vertical  compound  condensing,  the 
cylinders  being  direct  acting.  The  small  cylinder  operates  a  lever 
which  works  the  air  pump,  the  feed  pump,  and  the  circulating 
pump,  all  of  which  are  vertical,  single  acting,  and  have  the  same 
stroke  of  piston.  The  air  pump  discharges  into  an  open-topped 
hot-well  or  reservoir  placed  above  the  outboard  waterline,  the  top 
of  the  air  pump  being  closed. 

The  cylinders  are  separated  to  allow  the  valve  chests  to  be  placed 
between  them,  with  sufficient  additional  space  for  the  removal  of 
their  covers.  The  valves  of  each  cylinder  are  a  plain  three-ported 
slide  with  a  slide  cut-off  on  its  back  ;  these  valves  are  not  counter- 
balanced, but  work  with  the  full  steam  pressure  on  their  backs. 
The  three-ported  slides  or  steam  valves  are  operated  each  by  a 
Stephenson  link  and  two  eccentrics,  which  serve  as  a  reversing  gear. 
The  cut-off  valves  are  each  operated  by  an  eccentric.  The  cut -off 
valve  of  the  small  cylinder  is  adjustable  ;  that  of  the  large  cylinder 
is  fixed  to  cut  off  at  about  one-third  of  the  stroke  of  the  piston  from 
the  commencement. 

The  engine  works  with  surface  condensation.  The  surface  con- 
denser is  composed  of  a  single  copper  pipe  placed  on  the  outside  of 
the  vessel,  beneath  the  water,  and  just  about  at  the  garboard  strake. 
This  pipe  commences  on  one  side  of  the  vessel  abreast  of  the  after 
or  large  cylinder,  extends  to  and  around  the  sternpost,  and  thence 
along  the  opposite  side  of  the  vesse  until  abreast  of  the  air  pump 
and  forward  cylinder.  The  diameter  of  the  pipe  continuously  de- 
creases from  the  end  at  which  it  receives  the  exhaust  steam  from  the 
large  cylinder  to  the  end  at  which  it  delivers  the  water  of  condensa- 
tion and  the  uncondensed  vapor  and  air  into  the  air  pump  whence 
they  are  thrown  into  the  hot-well  from  which  the  feed  pump  forces 
the  water  of  condensation  into  the  top  of  the  boiler  coil,  where 


Principal  Types  of  Yacht  Machinery.  1 73 

it  is  revaporized,  and  the  steam,  passing  first  into  the  small  cylinder 
and  thence  into  the  large  one,  is  finally  exhausted  into  the  con- 
densing tube.  It  is  essential  for  satisfactory  working  that  the 
delivering  end  of  this  tube  should  not  exceed  one-half  the 
diameter  of  its  receiving  end;  for  if  a  larger  diameter  be  given  to 
the  delivering  end,  a  part  of  the  exhaust  steam  will  pass  directly  to 
the  air  pump  over  the  water  of  condensation  in  the  tube.  The 
delivering  end  of  the  tube  must  be  small  enough  to  remain  com- 
pletely filled  with  water  for  the  exclusion  of  the  steam  from  the 
pump. 

The  after  main  pillow-block  serves  also  as  the  thrust  pillow-block, 
the  after  journal  of  the  crank-shaft  being  made  with  the  necessary 
thrust  rings  upon  it. 

From  the  "separator"  the  circulating  pump  continuously  draws 
water  and  forces  it  into  the  top  of  the  boiler  coil,  where  it  enters 
along  with  the  feed  water  from  the  feed  pump,  thus  maintaining  a 
forced  circulation  through  the  coil  of  what  may  be  termed  "super- 
fluous feed." 

Details  of  the  engine: 

Diameter  of  the  small  cylinder 9  in. 

Diameter  of  the  piston  rod  of  the  small  cylinder I  %  in. 

Net  area  of  the  piston  of  the  small  cylinder 62.58  sq.  in. 

Stroke  of  the  piston  of  the  small  cylinder 18  in. 

Length  of  steam  port  of  small  cylinder 7.5  in. 

Breadth  of  steam  port  of  small  cylinder i-fV  in. 

Area  of  steam  port  of  small  cylinder 7.97  sq.  in. 

Length  of  exhaust  port  of  small  cylinder 7.5  in. 

Breadth  of  exhaust  port  of  small  cylinder 1.75  in. 

Area  of  exhaust  port  of  small  cylinder 13. 125  sq.  in. 

Clearance  of  piston  of  small  cylinder -ng  in. 

Diameter  of  the  large  cylinder 16  in. 

Diameter  of  the  piston  rod  of  the  large  cylinder I  ^  in. 

Net  area  of  the  piston  of  the  large  cylinder 200.02545  sq.  in. 

Stroke  of  the  piston  of  the  large  cylinder 18  in. 

Length  of  steam  port  of  large  cylinder 13  in. 

Breadth  of  steam  port  of  large  cylinder i-ns  in. 

Area  of  steam  port  of  large  cylinder 18.69  scl-  m« 

Length  of  exhaust  port  of  large  cylinder 13  in. 

Breadth  of  exhaust  port  of  large  cylinder 2.5  in. 

Area  of  exhaust  port  of  large  cylinder 32.5  sq.  in. 


FIG  62. — HERRESHOFF  ENGINE — END  ELEVATION. 


FIG.  63.— HERRESHOFF  ENGINE— SIDE  ELEVATION. 


176  Principal  Types  of  Yacht  Machinery. 

Clearance  of  piston  of  large  cylinder -fa  in. 

Diameter  of  the  air  pump 7  in. 

Stroke  of  the  piston  of  the  air  pump .6  in. 

Diameter  of  the  plunger  of  the  feed  pump I  ^  in. 

Stroke  of  the  plunger  of  the  feed  pump 6  in. 

Diameter  of  the  plunger  of  the  circulating  pump i^s  in. 

Stroke  of  the  plunger  of  the  circulating  pump 6  in. 

Length  of  the  condensing  pipe          53  ft. 

Inside  diameter  of  condensing  pipe  at  exhaust  steam  end 5  in. 

Continuous!    decreasing  to  inside  diameter  at  air  pump  end  of  ...  2  in. 

Thickness  of  the  metal  of  the  condensing  pipe  (copper) 'iV  in. 

Exterior  surface  of  the  condensing  pipe 50.2983  sq.  ft. 

Length  of  the  connecting  rods  between  centers 49^  in. 

Diameter  of  screw-shaft  inside  of  brass  casing 3^  in. 

Length  in  the  vessel  occupied  by  the  engine 66  in. 

Breadth  in  the  vessel  occupied  by  the  engine 48  in. 

Height  of  engine  above  center  of  crank  shaft 96  in. 

The  screw  of  the  Leila  is  of  brass  and  four-bladed,  the  pitch 
being  uniform,  the  leading  and  following  edges  are  parallel,  when 
projected  on  a  plane  parallel  to  the  axis.  The  diameter  is  4  ft. 
7  in.;  diameter  of  hub  7  in.  Pitch  8ft.;  projected  area  upon  a 
plane  at  right  angles  to  the  axis  is  6.59  sq.  ft. 

A  summary  of  the  Leila's  performance  is  given  below.  The 
vessel  was  not  forced  to  highest  speed,  but  worked  at  ordinary  rate 
under  natural  draft  only.  Artificial  draft  would  have  given  higher 
speed  of  vessel  at  increased  expenditure  in  fuel.  Steam  was  cut  off 
at  0.4  of  stroke  in  small  cylinder  and  0.36  in  large  cylinder. 

Steam  pressure  in  boiler 129  Ibs. 

Number  of  times  steam  was  expanded 7 

Vacuum  in  air  pump 25.8 

Number  of  revolutions  per  minute 221.5 

Piston  speed 664. 5 

Speed  of  vessel  per  hour  in  miles JSoO 

Speed  of  vessel  per  hour  in  knots 13-45 

Slip  of  screw  in  per  cent,  of  speed 23 

Initial  pressure  in  small  cylinder 135  Ibs. 

Initial  pressure  in  large  cylinder 45  Ibs. 

Indicated  horse  power 150 

I.  H.  P.  per  ton  of  displacement 4.02 

Weight  of  boiler  and  contents  per  I.  H.  P 72  Ibs. 

Heating  surface  per  I.  H.  P 3. 5  sq.  ft. 


Principal  Types  of  Yacht  Machinery.  177 

Grate  surface  per  I.  H.  P 0.173  sq.  ft. 

Coal  consumed  per  I.  H.  P.  per  hour 2.21  Ibs. 

Coal  consumed  per  square  foot  of  grate 12.8  Ibs. 

Coal  consumed  per  square  foot  of  heating  surface 0.68  Ibs. 

The  coal  used  was  common  anthracite,  leaving  15  per  cent,  of 
clinker.  With  selected  coal  of  the  same  grade  as  Nixon's  Naviga- 
tion, the  consumption  would  have  been  reduced  to  2  ll^s.  per  I.  H.  P. 
per  hour.  The  maximum  speed  recorded  for  yachts  of  the  Leila 
class  is  22.8  miles  or  19  knots. 

This  has  since  been  surpassed  in  the  latest  yachts  of  Herreshoff 
construction,  the  most  notable  of  which  are  the  launch  Henrietta 
and  the  Stiletto,  now  the  property  of  the  U.  S.  Government. 

The  Stiletto  is  very  light  but  strong,  a  frame  of  bent  oak 
well  fastened  to  heavy  keel,  and  garboards  with  two  heavy  oak 
wales  on  each  side,  making  a  very  strong  framework,  which  is 
covered  with  a  double  skin  of  white  pine,  with  decks  of  the  same 
material.  The  hull  is  divided  by  watertight  bulkheads.  The  most 
peculiar  feature  is  the  upper  portion  above  the  hull  proper. 
Instead  of  the  ordinary  deck  and  cabin  trunk  the  sides  are  carried 
up,  as  shown,  beveling  slightly,  high  amidships  and  low  at  the  ends, 
the  crown  being  almost  the  reverse  of  the  sheer  line.  These  two 
sides  each  form  a  trussed  girder,  stiffening  the  entire  hull,  while  the 
weight  is  mostly  amidship.  From  their  shape  they  offer  little 
resistance  to  the  wind.  Her  dimensions  are :  Length  over  all, 
94ft.;  beam,  nft.,  (a  proportion  of  8V\),  and  depth  of  hold, 
7  ft.  9  in. 

The  engine  is  compound,  12  and  12  x  12,  capable  of  450  turns 
per  minute.  Annular  valves  are  used,  cutting  off  generally  at  y%. 
The  weight  of  the  engines  is  4,275  Ibs.,  and  they  can  work  up  to 
450  H.  P.  with  forced  draft.  Many  of  the  parts  are  of  steel,  the 
shaft  being  4  in.  diameter.  The  wheel  is  4ft.  diameter  with  6ft. 
6  in.  pitch,  four-bladed.  The  boiler  is  a  sheet-iron  box  7  ft.  square, 
set  on  a  fire-brick  foundation  ;  the  upper  part  of  this  box  tapers  into 
the  stack,  like  an  inverted  mill  hopper.  Inside  the  fire  box  is  6  ft. 
3  in.  square.  Just  above  the  fire  is  a  row  of  tubes  3^2  in.  in 
diameter  running  side  by  side  thwartship,  each  tube  being  con- 


[i78] 


Principal  Types  of  Yacht  Machinery.  179 

nected  to  its  neighbor  at  alternate  ends.  Above  are  six  other  sets, 
decreasing  in  size  to  i^in.  diameter,  the  second  set  running  fore 
and  aft,  the  third  parallel  with  the  first,  etc.,  making  practically  one 
long  tube,  folded  compactly  into  a  small  space.  The  upper  or 
smaller  end  of  this  coil  is  connected  with  the  feed  pump,  and  the 
lower  and  larger  end  with  the  separator,  a  vertical  cylinder  4ft. 
long  and  i8in.  diameter,  placed  in  front  of  the  boiler.  On  this  are 
the  gauges  and  cocks.  The  water  and  steam  entering  here  from 
the  pipes  are  separated,  the  latter  passing  to  the  high-pressure 
cylinder.  The  water  is  used  continuously,  the  only  waste  being  by 
the  whistle  or  leakage.  The  water  pumped  into  the  boiler  at  the 
top  of  the  coil,  converted  into  steam  as  it  descends  through  the 
pipes,  passes  to  the  separator,  thence  to  the  high-pressure  cylinder, 
the  receiver,  low-pressure  cylinder,  and  condenser,  and  finally  to 
the  feed  pump  and  boiler,  any  loss  being  supplied  by  an  injector. 
Tv  e  heating  surface  is  615  sq.  ft.  and  the  boiler  works  up  to  160  Ibs. 
pressure.  The  total  weight  is  13,637  Ibs.  The  consumption  of 
coal  is  about  2  Ibs.  per  H.  P.  per  hour.  The  displacement  of  Stiletto 
is  28  tons. 

VERTICAL    DIRECT-ACTING    ENGINES. 

In  direct-acting  simple  engines,  vertical  tubular  or  horizontal 
tubular  boilers,  the  long  experience  of  the  New  York  Safety  Steam 
Power  Company  has  placed  their  yacht  machinery  in  the  front 
rank  in  the  East,  and  many  examples  of  their  work  can  be  met  with 
in  foreign  waters.  The  engines,  of  which  an  illustration  has  been 
given  in  the  first  chapter,  are  designed  and  constructed  to  possess 
great  strength,  with  compactness  of  form,  freedom  of  action,  sim- 
plicity and  perfection  of  details.  Accurate  workmanship  and  fine 
finish  play  an  important  part  in  performance  and  wear,  particularly 
at  the  high  speeds  now  requisite,  when  journals  are  apt  to  heat  and 
breaking  down  is  not  infrequent.  In  grace  of  form  and  proper 
distribution  of  material  the  engines  under  consideration  are  without 
rival.  For  launches  and  yachts  not  intended  primarily  for  distant 
cruising,  the  absence  of  the  compound  feature  is  not  without  its 


[i8o] 


1x8x1 


1 82  Principal  Types  of  Yacht  Machinery. 


advantages.     Fuel  economy  is  not  such  an  important  item  in  such 
boats  as  reliability  and  moderate  first  cost. 

The  vertical  engine  has  two  bearings  for  the  crank  shaft  in  the 
frame,  both  being  cast  solid  with  the  standard  or  column,  as  are 
also  the  cross-head  slides.  There  can  be  no  derangement  of  the 
line.  On  larger  sizes  an  adjustable  thrust-bearing  is  secured  to  the 
engine  frame  in  addition.  The  cranks  are  counterbalanced,  crank 
shaft,  piston  rod,  valve  stem,  cross  head,  pin,  etc.,  are  of  steel.  The 
link  motion  has  a  cut-off  index,  by  which  the  expansion  can  be 
regulated.  In  engines  larger  than  7X9  the  main  valve  is 
"balanced,"  that  is,  so  arranged  that  it  is  not  subject  to  the  steam 
pressure  on  its  back  in  the  steam  chest  and  therefore  not  pressed 
hard  against  the  valve  seat,  thus  obviating  undue  friction.  The 
steam  and  exhaust  openings  are  double,  so  that  the  steam  may  have 
free  exit  and  entrance  and  preserve  the  initial  pressure  in  cylinder 
near  that  of  the  boiler.  Engines  are  fitted  with  link  reversing  gear, 
cylinder  lubricator,  stop  valve,  drip  cocks,  pry  wheel  for  starting 
when  on  the  dead  center,  couplings  and  oil  cups.  The  details  of 
some  leading  sizes  are  given  in  the  table  : 


Size  of 
Cylinder 
Diameter. 
Stroke. 

Diameter 
of  Crank 
Shaft. 

Height 
from  Floor 
to   Top 
of  Cylinder 

Weight  of 
Engine. 

Diameter 
of  Base. 

Size  of  Boat  for  Which  Suitable. 
(Approximate.) 

Inches. 

Inches. 

Inches. 

Pounds. 

Inches. 

Length.         Beam.         Draft. 

3     X  5 

1% 

36^ 

230 

13 

25  ft.        5      ft.     Sin.  27  in. 

3>^X  5 

li% 

36^ 

270 

13 

28ft.        5      ft.  10  in.  28  in. 

4X6 

2 

44^ 

295 

I5J4 

30  ft.        6      ft.              30  in. 

5t   X  6 

2 

315 

32ft.        6^  ft.              32  in. 

2/"£ 

51 

460 

18  2 

35ft.        7     ft-              35  in. 

6j^X   7 

23^ 

51 

545 

18 

38ft.        7^  ft.              38  in. 

7X9 

3 

63^ 

825 

26 

40  ft.        8      ft.              40  in. 

8X9 

3 

63^ 

1  200 

26 

45  ft.      10      ft.              48  in. 

9     Xi2 

4 

77^ 

22OO 

26 

65  ft.      ii      ft.              54  in. 

10       XI2 

4 

77^ 

2800 

26 

70  ft.      12      ft.              60  in. 

12       XI2 

5 

90 

3500 

32 

75ft.      15      ft.              60  in. 

The  applicability  of  the  screw  to  extreme  light  draft  is  illustrated 
in  the  plans  of  a  launch  32ft.  long  and  8ft.  beam.  To  obtain 
enough  area  of  wheel  upon  only  1 2  in.  immersion,  three  wheels  take 
the  place  of  the  usual  single  or  even  twin  screws,  all  three  being 
driven  by  gears  from  the  single-cylinder  engine.  All  the  wheels  are 


Principal  Types  of  Yacht  Machinery.  183 


kept  above  the  keel  line,  a"nd  no  skag  is  introduced.  The  launch 
may  therefore  "take  the  ground  "  without  risk,  an  immunity  which 
will  be  appreciated  by  sportsmen  or  others  navigating  unknown 
waters  or  where  shifting  bars  render  charts  unserviceable. 


FIG.  67. — OPEN  STEAM  LAUNCH. 

Launch  boilers  are  of  the  vertical  tubular  style,  being  compact, 
light  and  simple,  and  also  as  economical  and  safe  as  any  other  style 
when  built  to  good  proportions.  For  decked  yachts  the  horizontal 
fire  tubular  boiler  is  preferred,  owing  to  its  lower  center  of  gravity. 
The  mountings  and  attachments  comprise  ash  pan,  grates,  smoke 
bonnet,  stack  with  guys,  safety  valve,  gauges,  blow-off  cocks,  feed 
check,  feed  globe  valve,  stop  valve  and  whistle.  The  hydraulic  test 
is  200  Ibs.  Proportions  of  vertical  boilers  are  given  in  the  table: 


• 

Diameter  of 
Boiler. 

Height  of 
Boiler. 

Tubes. 

Heating 
Su  rf  ac  e, 
Square  Feet. 

Size   of  Engine 
Cylinder  to  be 
Driven.    • 

Number  of. 

Diameter. 

28 

48 

84 

I* 

60 

3     X   5 

30 

48 

150 

i# 

95 

3^X   5 

33 

48 

180 

*x 

104 

4     X  6 

36 

48 

204 

*x 

137 

5     X  6 

36 

54K 

204 

i# 

!97 

5^X  7 

44 

66 

1  20 

2 

205 

6^X  7 

46 

76 

136 

2 

256 

7X9 

48 

82 

144 

2 

280 

8X9 

50 

82 

i  So 

2 

380 

9     Xi2 

54 

85 

204 

2 

430                      10       XI2 

h 

"    n 
o  '5 


*:j 


[186] 


[x88l 


Principal  Types  of  Yacht  Machinery.  1 89 


The  steamers  of  the  Tampico  and  Mexican  Trader  class,  although 
not  strictly  yachts,  could  be  readily  altered  to  such  by  trifling  modi- 
fications in  their  interior  arrangements.  For  cruising  the  models 
are  quite  suitable,  being  able  and  roomy  and  more  serviceable  than 
lean  craft  cut  away  for  the  sake  of  the  highest  speed.  The  general 
plans  of  these  vessels  will  also  be  interesting  in  determining  the 
design  of  new  yachts. 

The  number  of  launches  and  fast  yachts  on  the  great  fresh-water 
lakes  and  Western  rivers  has  increased  at  a  rapid  rate  during  the 
past  years,  and  a  very  large  fleet,  counting  into  the  thousands,  is 
destined  to  be  called  into  existence  with  the  growing  population  and 
wealth  of  the  country.  Chicago  is  the  chief  center  for  construction 
of  machinery  and  hulls  of  the  most  approved  kind.  The  Willard 
high-speed  engine  has  taken  a  prominent  rank,  owing  to  its  reliability 
when  working  up  to  300  turns  as  a  regular  working  speed.  This 
engine  has  proportions  and  material  which  are  the  result  of  the  ex- 
tensive experience  of  Messrs.  C.  P.  Willard  &  Co.,  of  Chicago,  whose 
practice  in  the  most  popular  sizes  is  shown  below: 


Diameter 
Cylinder. 

Stroke. 

Revolutions. 

Boiler 
Pressure. 

Actual   Indi- 
cated Horse 
Power. 

Height. 

Weight. 

875  'bs. 
1000  Ibs. 

6  in. 
7  in. 

8  in. 
Sin. 

350 
350 

130  Ibs. 
i3olbs. 

40 
60 

54  in. 
54  in. 

The  crank  shaft  is  of  steel,  crank  arms  being  fitted  with  counter 
balances  bored  to  fit  crank  discs.  The  after  journal  forms  the  thrust 
bearing,  the  thrust  from  screw  being  taken  by  four  steel  rings,  solid 
with  the  shaft.  Steam  is  cut  off  by  a  slide  valve  at  half  stroke.  The 
illustrations  show  the  engine  in  place,  bolted  to  the  engine  keelsons, 
and  also  in  section.  The  piston  is  conical  for  strength  and  securing 
the  rod.  Cross  head  is  of  bronze  with  the  piston  rod  threaded  into 
it  and  secured  by  a  jam  nut.  The  boilers  built  by  the  same  firm 
have  previously  been  described. 


FIG.  73. — THE   WILLARD   HIGH   SPEED    MARINE   ENGINE — SECTIONAL   VIEW. 
Chas.   P.  WILLARD  &  Co.,  CHICAGO. 

[190] 


FIG.  74.— THE  WILLARD  HIGH  SPEED  MARINE  ENGINE— FRONT  ELEVATION. 
Chas.    P.  WILLARD  &  Co.,  CHICAGO. 


[I92] 


Principal  Types  of  Yacht  Machinery.  193 

The  common  use  of  the  stern  paddle-wheel  in  the  freight  and 
passenger  steamers  of  Western  rivers  has  led  to  a  general  apprecia- 
tion of  its  merits.  It  is  considered  equally  as  efficient  for  power  or 
speed  as  the  side-wheels  adopted  on  the  steamers  of  Eastern  rivers. 
For  the  many  thousands  of  miles  of  smooth-water  navigation  through- 
out the  West,  the  stern-wheel  is  certain  to  hold  its  own  in  public 


.  76. — STERN -WHEEL  LAUNCH  FOR  WESTERN  RIVERS. 


estimation.  In  the  uncharted  headwaters  of  many  of  the  great 
river  systems,  the  occurrence  of  bars,  snags  and  shoal  patches  renders 
the  stern-wheel  better  adapted  than  the  screw  for  light  draft  in 
connection  with  moderate  first  cost,  and  it  can  be  applied  with  less 
expense,  weight  or  breadth  of  space  than  the  side-wheel.  The 
general  arrangement  of  launches  driven  by  a  wheel  over  the  stern  is 
shown  in  the  accompanying  illustration. 


194          Principal  Types  of  Yacht  Machinery. 

The  hulls  are  flat  bottom  with  a  round  up  in  the  run,  and  the  sides 
are  either  straight  from  bottom  to  sheer  line  or  have  a  slight  swell 
amidships  and  some  flare  forward  according  to  the  moulding  of  the 
frame.  Such  launches  can  easily  be  shipped  on  a  flat-car  to  points 
of  destination.  Machinery  consists  of  a  submerged-tube  vertical 
boiler,  as  described  in  the  chapter  on  boilers  and  double  engines, 
with  horizontal  cylinders  in  the  stern,  connected  direct  to  the  stern- 
wheel  shaft.  They  are  reversed  and  controlled  by  a  single  lever 
and  throttle-valve.  The  details  of  a  40  ft.  launch  built  by  Willard 
&  Co.,  are  as  follows  : 

Length  of  hull,  feet 33 

"          boat,    "    overall 40 

Beam,  outside,  feet 8 

Depth,    feet ' 3 

Draft,  inches 16 

Number  of  persons  it  will  carry 30 

Approximate  speed,  miles  per  hour 10 

consumption  of  soft  coal,  per  10  hours,  pounds 400 

Actual  horse  power  with  70  Ibs.  of  steam. 10 

Engines — two  in  number — diameter  of  cylinder,  inches 5 

stroke,  inches 20 

Vertical  boiler,  diameter,  inches 40 

"       height,  inches 53 

Diameter  of  stern-wheel,  feet 7 

Sea-going  launches  do  not  differ  from  those  intended  for  river 
purposes,  except  in  being  more  or  less  completely  decked  for  keep- 
ing out  the  sea.  A  good  deal  of  cruising  about  the  coast  and  in 
such  open  arms  of  the  sea  as  Chesapeake  Bay  can  be  got  out  of  a 
launch  of  able  proportions. 

Cruising  launches,  not  being  built  solely  for  speed,  are  more 
reasonable  in  first  cost,  can  be  depended  upon  for  strength  and  a 
long  life,  and  their  engines  having  a  lower  velocity  of  piston  than 
those  of  racing  craft,  give  much  less  trouble  and  annoyance,  while 
the  coal  account  is  also  less  serious  an  item  of  expense.  One  or 
two  hands  compose  the  crew.  Fuel  can  be  carried  for  an  extended 
period,  as  a  minimum  displacement  is  no  object ;  and  with  ample 
draft,  dead  rise  and  an  easy  bilge,  very  fair  rough-water  qualities 
may  be  secured,  so  that  this  type  is  especially  adapted  for  family 


1x95] 


196  Principal  Types  of  Yacht  Machinery. 

use,  for  sportsmen,  for  knocking  about,  and  in  short  for  steam 
cruising  on  small  tonnage.  Persons  interested  in  mechanics,  who 
like  to  observe  the  working  of  machinery,  experiment,  compare, 
investigate  old  theories  and  perhaps  build  others  in  their  place,  who 
like  besides  the  romance  of  adventure,  ever-changing  scenes  and 
weather,  and  seek  the  health  of  a  life  in  the  open  air,  will  do  best  to 
invest  in  a  cruising  launch  and  take  time  and  comfort.  Racing 
steamers  are  good  in  their  way,  but  they  cost  more  to  begin  with, 
and,  if  you  are  not  in  a  hurry,  offer  less  in  return  for  your  money 
than  the  staid  but  solid  cruiser.  A  fine  example  is  the  launch  built 
for  an  Oriental  potentate  by  J.  S.  White,  of  Cowes,  England.  The 
boat  is  decked  fore  and  aft,  with  the  exception  of  a  small  cockpit 
forward.  There  is  a  hatch  over  the  boiler  space  surrounded  by  a 
hand-rail  and  another  aft  over  the  quarters  for  the  crew.  All  these 
can  be  battened  down  with  tarpaulins  should  the  craft  be  caught  in 
bad  weather.  For  use  in  waters  likely  to  be  rough  the  windows  in 
the  cabin  can  be  kept  much  smaller  and  every  other  panel  solid,  so 
that  if  well  built,  braced  and  fastened,  the  danger  of  being  stove  in 
forward  is  removed.  The  accommodations,  besides  cockpit  and 
ample  locker  room  for  stores,  fishing  tackle  and  shooting  outfit, 
consist  of  a  saloon  12  ft.  long,  w.  c.,  pantry  and  galley,  situated 
forward  of  the  machinery.  The  latter  occupies  i6ft.,  and  the 
remaining  length  abaft  has  two  berths  and  storage  for  the  crew. 
She  may  be  steered  by  tiller  on  deck  aft  or  by  a  wheel  on  the  after 
cabin  bulkhead,  a  position  affording  a  good  view  ahead,  and  pro- 
tecting the  steersman  from  the  weather  and  sea.  This  launch  made 
a  passage  from  Cowes  to  London  in  the  teeth  of  a  strong  easterly 
gale.  Her  length  is  50 ft.;  beam,  ioft.;  draft  forward,  2ft.  ioin.; 
aft,  3  ft.  6  in. ;  displacement,  n  tons;  screw,  four  blades,  diameter 
3ft.  6  in.;  pitch,  3ft.  3 in.  to  4ft.  6 in.;  two  cylinders,  diameter 
7%  in.;  stroke,  6  in.;  grate  surface,  5. 5  sq.ft.;  heating  surface, 
215  sq.  ft.  At  the  speed  of  11.03  miles  (9-58  knots)  per  hour,  the 
number  of  revolutions  was  268,  and  the  gauge  showed  761bs.  per 
square  inch.  With  a  mean  effective  pressure  in  the  cylinder  equal 
to  75  per  cent,  of  the  boiler  pressure,  the  power  developed  would  be 
43.4  I.  H.  P.,  which  must  be  considered  very  satisfactory  in  so  small 


198  Principal  Types  of  Yacht  Machinery. 

a  boat.     The  hull  is  built  of  teak  and  mahogany,  laid  in  two  layers 
diagonally,  coppered  and  copper  fastened. 

Along  the  American  coast,  where  harbors  are  frequent  and  easily 
made,  extensive  cruises  have  been  undertaken  by  yachts  with  high 


FIG.  79. — THE  FALCON  IN  THE  BAY  OF  FUNDY. 


superstructures.  Sufficient  buoyancy  to  hull  is  a  first  requisite  in 
this  semi-seagoing  type,  so  that  the  vessel  shall  lift  quickly  to  a  sea, 
and  the  deck  houses  need  to  be  of  strong  construction,  well  braced, 
with  wood  or  iron  ports  to  close  the  "  windows  "  when  the  sea  is 
running  high.  The  boiler  and  engine  space  should  be  inclosed  with 


Principal  Types  of  Yacht  Machinery.  1 99 

iron  or  stout  wooden  bulkheads,  so  that  damage  to  the  superstructure 
will  not  flood  the  stoke  hole  and  put  the  fires  out.  The  cabins 
should  be  built  upon  a  complete  deck  across  the  hull,  and  the  hatches 
for  access  to  the  hold  must  be  surrounded  by  high  coamings 
provided  with  covers.  If  the  sea  can  find  its  way  below  easily,  the 
risk  of  swamping  would  be  great.  Flush  decks  are  now  preferred, 
as  they  can  easily  be  had,  even  in  a  very  small  steamer,  if  she  be 
well  proportioned,  and  at  no  greater  cost  than  the  "cabin  houses." 
For  river  and  harbor  yachting,  however,  the  style  illustrated  by  the 
Falcon  has  its  good  points  The  accommodations  are  lofty  and  cool, 
and  a  good  view  is  afforded  from  the  cabin  windows  or  from  the 
elevated  position  on  the  upper  or  hurricane  deck.  The  Falcon, 
when  owned  by  Mr.  R.  T.  Bush,  of  Brooklyn,  did  some  extensive 
coasting  in  1884,  proceeding  from  New  York  to  St.  John,  N.  B.,  and 
the  head  of  the  Bay  of  Fundy.  She  was  out  of  sight  of  land  on 
several  occasions,  and  met  rather  bad  weather,  but  was  reported  as 
going  through  it  in  good  shape.  An  idea  of  her  hull  can  be  got 
from  the  sketch,  showing  the  steamer  left  high  and  dry  by  the  dock 
of  Windsor,  the  tide  falling  60  ft.  in  the  Bay  of  Fundy,  and  receding 
six  miles  from  the  dock. 

The  Falcon  is  120  tons  burden,  io6ft.  long,  16  ft.  beam  and  draws 
7  ft.  aft. 

Regular  seagoing  cruising  yachts  are  destined  to  attract  more 
attention  in  the  future  than  in  the  past.  Hitherto  almost  every 
steam  yacht  in  America  has  been  built  with  the  idea  of  maximum 
speed  uppermost,  and  seaworthiness  has  received  little  consideration 
except  in  the  largest  vessels.  In  course  of  time  the  cruiser  will 
separate  from  the  racer  under  steam  just  as  he  ha£  done  in  yachts 
propelled  by  sail.  Only  a  small  fraction  of  the  sailing  fleet  is  given 
to  racing  now  that  such  sport  involves  great  expense  and  efforts 
strained  to  the  utmost,  permitting  not  a  moment's  relaxation. 
Racing  under  steam  is  even  more  extravagant  in  first  cost.  A 
cruising  vessel,  planned  intentionally  as  such,  will  boast  of  less  power 
than  the  racing  machine,  hence  first  cost  of  engines  and  boiler  will 
be  less.  Piston  speed  will  not  be  so  great,  and  a  cheaper  grade  of 
machinery  will  suffice.  Bunker  capacity  must  be  greater  for  distant 


2OO  Principal  Types  of  Yacht  Machinery. 

voyages,  where  fuel  is  not  to  be  had  as  readily  as  between  New 
York  and  the  Maine  coast.  The  space  given  up  to  motive  power  is 
restricted,  and  roomy  accommodations  call  for  more  beam  than  in 
the  racer.  Additional  stowage  for  stores  must  be  supplied  in  the 
cruiser,  the  equipment  must  be  more  complete  and  the  rig  of  service- 
able character.  The  hull  must  be  stronger  and  show  more  free- 
board. For  these  reasons  the  perfect  cruiser  must  be  a  beamier, 
deeper  and  fuller  vessel  than  the  racer.  She  will  also  be  more 
economical  to  build,  and  can  be  run  with  fewer  hands.  Nearly  the 
entire  British  fleet  of  steam  yachts  belongs  to  the  cruiser  class,  with 
a  speed  from  7  to  10  knots  for  vessels  of  moderate  dimensions, 
although  ii  and  12  is  attained  in  the  larger  craft.  Speed  is  kept 
secondary  to  completeness  and  adaptability  for  long  voyages.  In 
these  cruisers  it  is  possible  to  obtain  very  fair  internal  arrangements 
and  seagoing  powers  on  small  dimensions.  While  the  high-speed 
racer  of  60  ft.  length  is  little  more  than  a  long  launch,  lightly  decked 
and  half  fitted,  the  cruiser  of  the  same  length  may  be  a  regular 
vessel  in  all  that  implies. 

The  Chemcheck,  built  by  Miller,  Tupp  &  Rouse,  of  London,  stands 
as  an  example  of  a  large  class  deservedly  popular  in  England.  She 
was  intended  for  cruising  in  the  Mediterranean.  Her  extreme  length 
is  but  65ft.  with  a  beam  of  12  ft,  while  the  draft  of  5ft.  is  very 
moderate.  Her  construction  is  such  as  to  fit  her  for  sea  work  and 
hard  service,  the  frame  being  of  English  oak  and  American  elm' well 
fastened.  The  planking  is  of  teak  coppered,  and  she  is  finished 
throughout— bulwarks,  rail,  deck  houses,  skylights  and  cabins — with 
the  same  wood.  Her  general  appearance  is  that  of  the  ordinary 
English  schooner  yacht,  the  same  bow,  with  round  bright  bowsprit, 
high  bulwarks  (15  in.)  and  a  long  counter,  while  her  general  propor- 
tions, above  and  below  water,  are  designed  to  give  her  sea-going 
power  with  good  speed  under  sail  alone.  The  rig,  as  shown,  is  that 
of  a  two-masted  schooner  with  spars  and  sails  of  such  size  as  to  be 
of  real  service.  Of  course  in  so  small  a  boat  the  bunker  space  is 
limited,  and  coal  for  long  trips  cannot  be  carried,  but  this  dis- 
advantage, attendant  on  all  types  of  steam  yachts  of  similar  size,  dis- 
appears when  the  ability  to  get  somewhere  under  sail  is  taken  into 


2O2  Principal  Types  of  Yacht  Machinery. 

account.  Her  four  beams  to  length  give  good  proportions  for  sail- 
ing, and  under  the  rig  she  is  provided  with  she  is  a  handy  and 
efficient  little  vessel  under  canvas  alone.  The  power  provided  is  a 
pair  of  compund  engines,  surface  condensing,  with  inverted  cylinders 
9%  and  17  in.  by  9^2  in.  stroke.  They  are  fitted  with  a  valve 
reversing  gear  patented  by  the  builders.  The  air  and  circulating 
pumps  are  driven  by  an  independent  engine,  a  donkey  pump  is  fitted 
to  the  boiler,  and  also  a  bilge  injector.  The  screw  is  of  48  in.  diam- 
eter, 6  ft.  pitch,  fitted  to  a  3  in.  iron  shaft.  Steam  is  provided  by  a 
return  tubular  boiler  60  in.  diameter  and  7  ft.  long,  with  forty-two 
2%  in.  tubes.  The  boiler  is  tested  to  150  Ibs.,  the  working  pressure 
being  60  Ibs. 

The  accommodations  are  well  shown  in  the  plan.  Forward  is  a 
chain  locker,  A,  and  storeroom.  The  main  saloon,  B  B,  is  fitted  with 
berths,  while  by  day  it  serves  as  cabin  and  dining  room.  From  it 
opens  a  toilet  room  and  w.  c.,  C,  and  also  a  pantry,  D.  Amidships  is 
the  engine  room  F,  fitted  like  the  rest  in  teak,  and  at  the  sides  the 
coal  bunkers,  E  E.  The  ladies'  cabin,  G,  is  directly  abaft  the  engine 
room.  It  is  fitted  up  with  two  berths  and  a  skylight.  The  after 
portion  of  the  yacht,  H  H,  is  fitted  up  as  a  galley  and  quarters  for 
the  crew.  The  elegance  and  luxury  of  larger  craft  are  lacking,  but 
the  essentials,  a  staunch  little  hull,  full  equipment  and  cosy  quarters, 
are  found  in  an  excellent  combination.  A  still  smaller  yacht  of 
similar  design  is  the  Iris,  built  in  1883  by  the  same  firm,  and  also 
stationed  in  the  Mediterranean.  Her  length  over  all  is  but  60  ft., 
beam  n  ft.,  draft  5  ft.,  depth  of  hull  6  ft.  6  in.  She  is  built  of  teak, 
coppered,  and  is  schooner  rigged,  being  much  like  the  Chemcheck. 
Her  engines  are  9  and  16  in.  X  9  in.,  boiler  57  in.  diameter  and  6  ft. 
long,  screw  48  in.  diameter.  Her  average  speed  is  10^2  knots.  She 
made  the  voyage  through  the  Bay  of  Biscay  to  the  Mediterranean 
and  is  now  stationed  at  Messina. 

A  large  sea-going  yacht  of  429  tons,  builder's  measurement,  is 
shown  in  the  frontispiece. 

The  Shaugraun  was  built  at  Newburg,  N.  Y.,  in  1879.  She  is 
169  ft.  long  over  all.  148  ft.  7  in.  long  on  waterline,  beam  26  ft.  2  in., 
depth  of  hold  12  ft.,  draft  of  water  10  ft.  2  in.,  cubic  contents,  26,138. 


Principal  Types  of  Yacht  Machinery.  203 

Engines  are  double  compound  surface  condensing,  with  cylinders  of 
23  and  42  in.  diameter  and  stroke  of  30  in.  She  has  two  return 
tubular  boilers,  each  with  two  furnaces,  the  total  heating  surface 
being  2,000  sq.  ft.,  and  working  pressure  loolbs.  Propeller  is  9  ft. 
6  in.  diameter.  The  coal  bunkers  are  of  70  tons  capacity.  Fore- 
mast is  80  ft.,  foretopmast  44  ft.,  mainmast  83  ft.,  topmast  44  ft.,  bow- 
sprit outboard  32  ft.,  mainboom  5 7  ft.,  foreboom  46ft.-  Among  her 
boats  she  carries  a  25  ft.  steam  pinnace. 


DIMENSIONS     OF    AMERICAN    STEAM     YACHTS. 


Name. 

Builder. 

Length 
on 
deck. 

LWL 

Beam. 

Depth 

Draft. 

.      Engines. 

v      .,                (      Herreshoff,     ) 
Xanthe  1   Bristol,  R.I.   f 

45 

41 

9 

4-3 

2.9 

j  C.   I.  2  cyl.  $yz   and  7X7. 
1     Coil  boiler,  3^  ft.  diam. 

Galatea           •!  R  McGiehan'  I 
ea  '  '  '  '    1  Pamrapo,  N.J.  f 

52 

47 

10.6 

4-4 

3.2 

-j  C.  I.  2  cyl.  6  and  14X9  ft. 

Sphinx 

(    John  Roach,   | 
1     Chester,  Pa.   f 

57 

53 

12.3 

4-3 

_        J  I.  i  cylinder,  11X10.   Boiler 

ii            5x7  #ft. 

Amelia            J   ?•  La^le>"  &   I 
'    |    Son,  Boston.    ) 

70 

65 

9 

5 

3  6     j  C.  I.  2  cyl.  8%   and   15X9. 
»               Boiler,  3X8  ft. 

Arrow             j  J.  F.  Mumm,  J 

78 

76 

10 

5 

s  2     j    I.   2  cyl.  ioX8ft.     Boiler, 

f                      5X6  ft. 

Stiletto  

j     Heireshoff,     j 
i  Bristol,  R.  I.   j 

94 

90 

II.  2 

8 

4  g     \  C.   I.  2  cyl.  12  and  21X12. 
1         Pipe  boiler,  7X7  ft. 

Leila  

j     Herreshoff,     | 
1   Bristol,  R.  I.    f 

100 

95-5 

15-4 

5.10 

6        j    C.  I.  2  cyl.  9  and  16X18. 
}       Coil  boiler,  7  ft.  diam. 

Uarda  

J    David  Bell,    } 
•j        Buffalo.        f 

no 

95 

I7.6 

8.6 

6.6 

(  C.  I.  2  cyl.,  14  and  24X16. 
I              Boiler,  6X9  ft. 

Utowana  — 

<    John  Roach,   i 
1    Chester,  Pa.    j 

138 

121.  6 

20.6 

11.7 

8.2 

\  C.  I.  2  cyl.  15  and   28X18. 
}     Hor.  tub.  boiler,  9X11  ft. 

Sigma  

j    John  Craig,    1 
|  Trenton,  Mich,  j 

154 

130 

21 

10 

8 

j  C.    I.  2  cyl.  16  and  24X28. 
(              Boiler,  8X13  ft. 

Yosemite... 

j    John  Roach,   ) 
(    Chester.  Pa.    j 

182 

170 

23 

18 

14 

j  C.  I.  2  cyl.  28^  and  40X33. 
I         Boilers,  n  and  12  ft. 

Stranger  

j  Cramp  &  Son,  1 
1   Philadelphia,  J 

190 

17° 

23.8 

14 

ia-5 

J  C.  I.  2  cyl.  24  and  44X24. 

1          Boilers,  io^X  ii  ft. 

Namouna.  .. 

j  Ward  &  Stan-  I 
1  ton,  Newburgh  I 

226.1 

217 

26.4 

15-4 

14-3 

j      Tan  C.  I.  4  cyl.  23  an-? 
(42X28.     2  boilers,  11X13  ft. 

I  Harlan  &  Hoi-  ) 

Nounnahal. 

•<      Hngsworth,     > 
|  Wilmington,  D.  ) 

233 

221 

30 

18.7 

14-3 

t  C.  I.  2  cvl.  34  and  60X36.  4 
")  boilers,  8^   and  10^X12  ft. 

Atalanta  .  .  . 

j  Cramp  &  Son,  | 
j  Philadelphia,    f 

250.3 

233-3 

26.4 

16 

13 

j  C.  I.  2  cyl.   30   and   60X30. 
1           2  boilers,  loX  ii  ft. 

(  Harlan  &  Hoi-  ) 

Alva  •<     hngsworth,     > 
/  Wilmington,  D.  ) 

285 

252 

32 

21.6 

16.8 

j  C.  I.  3  cyl.  32-  45  and  45X42. 
(        2  boilers,  10^X17  ". 

C.  I.,  compound  inverted  ;  Tan.  C.  I.,  tandem  compound. 


[2041 


206  Principal  Types  of  Yacht  Machinery. 

A  sea-going  vessel  of  English  design,  capable  of  long  voyages 
on  small  fuel  consumption  and  machinery  space  is  the  Carmen, 
designed  by  Mr.  J.  Beavor  Webb  for  Sir  Thomas  Freke,  the  order 
being  for  the  most  powerful  and  seaworthy  yacht  that  could  be 
built  of  200  tons,  a  voyage  from  England  to  the  China  Seas  being 
contemplated.  Besides  some  20  tons  of  stores,  furniture  and 
baggage  she  was  to  carry  a  sufficient  amount  of  coal  for  a  long 
voyage.  Carmen  was  built  of  iron  by  J.  Reid  &  Co.,  of  Glasgow, 
her  engines  being  built  by  Walker,  Henderson  &  Co.,  of  the  same 
place.  She  is  144  ft.  over  all,  no  ft.  waterline,  20  ft.  beam  and  n  ft. 
draft.  Her  displacement  is  208  tons,  indicated  horse  power  198, 
and  working  pressure  80  Ibs.  The  engines  are  compounded  14  and 
28X31  in.  The  hull  is  fitted  with  three  iron  bulkheads,  one  at  each 
end  of  the  engine  space  and  one  aft. 

The  interior  arrangements  are  excellent,  both  for  her  owners, 
guests  and  crew  of  fifteen.  The  latter  are  berthed  in  hammock  beds 
in  the  bow,  swung  in  a  large  forecastle,  forward  of  which  they  have  a 
washroom  and  w.  c.,  while  at  its  after  end  is  the  captain's  room, 
neatly  fitted,  the  space  under  the  bed,  both  here  and  in  all  other 
parts  of  the  ship  having  large  drawers.  Abaft  the  captain's  room  is 
a  dresser,  the  galley  being  above  in  the  deck  house.  The  forward 
saloon,  in  which  is  a  dining  table,  opens  into  four  large  staterooms, 
each  fitted  with  bed,  drawers,  toilet  table,  wardrobe  and  washstand. 
The  boilers  and  engines  occupy  no  more  than  their  fair  share  of 
space,  abreast  of  them  being  the  engineer's  and  fireman's  rooms  and 
bunkers  for  forty-two  tons  of  coal,  sufficient  for  about  2,700  knots 
steaming.  The  main  saloon  aft  of  the  engines  is  nft.  Xi9,  hand- 
somely furnished  with  a  fireplace  and  mantel,  sofas,  tables,  side- 
boards and  closets,  making  a  pleasant  resort  in  any  weather.  The 
owner's  cabin  is  a  good-sized  room,  with  bed,  toilet  table,  etc.,  and 
with  a  bathtub  below  the  flooring.  The  pantry  and  passage  take 
up  the  opposite  side  of  the  yacht,  and  further  aft  is  a  roomy  ladies' 
cabin,  with  two  berths,  two  sofas,  toilet,  etc.  Aft  of  this  are  closets, 
store  rooms,  and  a  room  for  the  maids.  The  deck  room  is  large, 
and  affords  a  fine  promenade  in  good  weather.  The  Carmen  carries 
four  boats,  a  gig  26ft.  X  4ft.  3in.,  a  dinghy  14  ft.  X  4ft.  6  in.,  a 


Principal  Types  of  Yacht  Machinery.  207 

cutter  1 8  ft.  6  in.  X  5  ft.  6  in.;  and  a  steam  launch  24ft.  x  5  ft.  6  in. 
The  galley  and  coal  box  on  deck  are  shown  in  the  upper  plan. 

She  ran  from  Plymouth  to  Gibraltar  in  4  days  13  hours,  thence  pro- 
ceeded to  Madeira  and  Santa  Cruz,  and  from  the  latter  place  to 
Barbados,  making  the  last  run  in  13  days  4  hours.  After  a 
cruise  in  the  West  Indies  she  returned  home,  running  from  Bermuda 
to  Holyhead  in  16  days.  On  the  trip  she  proved  herself  a  perfect 
sea  boat.  With  triple  expansion  engines  her  coal  consumption 
would  be  reduced,  and  the  42  tons  which  she  carries  would  serve  for 
about  3,400  knots  steaming. 


THE  WELLS  BALANCE  ENGINE. 

The  greater  durability,  smoothness  of  operation  and  lighter  con- 
struction obtained  from  balancing  reciprocal  motion  as  far  as 
possible  is  easily  understood.  The  usual  method  of  balancing  the 
weights  of  the  reciprocating  parts,  by  means  of  counter-weights  on 
the  crank,  accomplishes  only  a  part  of  the  object  desired.  It  is 
possible  to  prevent  either  horizontal  or  vertical  vibration  alone,  but 
impossible  to  prevent  both  at  the  same  time.  In  practice  a  com- 
promise is  therefore  adopted  with  the  result  that  running  at  a  piston 
speed  of  600  ft.  a  carefully  balanced  12X12  engine  exerts  at  every 
stroke  an  unbalanced  force  or  blow  of  over  a  ton.  This,  of  course, 
would  be  increased  with  heavier  connections  in  a  larger  engine,  or  a 
"steeple"  compound  of  the  same  size. 

The  relief  afforded  the  crank-pin  by  an  easier  cut  off,  lead  or 
cushioning,  does  not  prevent  external  vibration,  since  the  elastic 
steam  cushioning  transfers  the  blows  received  from  the  piston 
directly  to  the  cylinder  heads.  The  cumulative  effect  of  these 
regularly  repeated  blows  is  highly  injurious  and  is  worthy  of  serious 
consideration. 

A  perfect  balance  can  only  be  obtained  by  balancing  each  motion 
as  is  done  in  the  Wells  engine,  by  a  corresponding  opposite  motion 
of  the  same  weight,  exactly  in  the  same  plane.  In  this  engine,  the 
reciprocating  parts  move  in  opposite  directions,  and  are  so  propor- 
tioned that  one  piston  with  all  its  connections  exactly  balances  in 


2o8  Principal  Types  of  Yacht  Machinery. 

weight  the  other  piston  and  its  connections,  producing  a  perfect 
equilibrium  in  the  whole  circuit  of  the  crank-shaft  and  at  any  speed. 
This  permits  high  speed  without  vibration. 

As  the  cut  of  the  Wells  balance  engine  will  show,  the  large  piston 
has  two  rods  which  pass  outside  of  cylinder  A  and  are  connected  to 
the  two  outside  crank-pins,  which  are  set  opposite  the  middle  crank- 
pin  connected  to  the  small  piston. 

Steam  enters  both  cylinders  simultaneously,  driving  the  two 
pistons  in  opposite  directions.  The  cut  represents  high-pressure 
steam,  from  the  steam  chest  C,  forcing  down  the  small  piston  a,  and 
driving  out  the  exhaust  below  it  into  the  receiver,  while  at  the  same 
time  the  low-pressure  steam  from  the  receiver  is  forcing  up  piston  £, 
and  driving  the  exhaust  from  above  it  into  the  condenser  by  pas- 
sage E.  In  motion,  the  two  pistons  approach  and  recede,  the  cranks 
being  at  iSodeg. 

Steam  is  admitted  to  both  cylinders  simultaneously  ;  the  pressure 
against  one  cylinder  head  is  counteracted  by  an  equal  pressure 
against  the  other ;  therefore,  no  strains  are  transmitted  to  the  frame 
or  bed  of  the  engine.  The  steam  is  so  distributed  that  it  exerts  an 
equal  force  on  each  piston,  but  in  opposite  directions — the  thrust  of 
one  being  perfectly  counteracted  by  the  other.  The  crank  power  be- 
ing applied  equally  at  each  end  of  a  lever,  whose  center  or  fulcrum 
is  the  shaft,  it  will  revolve  in  the  main  bearings  without  friction. 
This  will  permit  the  use  of  high  steam  pressures  without  heating. 

Steam  is  distributed  by  the  piston  valve  c,  which  is  driven  by 
the  well  known  "Joy"  valve  gear,  especially  designed  to  give 
economical  results,  by  simple  and  direct  connections.  The  piston 
valve  has  been  adopted  because  it  is  simple,  perfectly  balanced, 
and  not  liable  to  get  out  of  order.  It  is  more  durable  than  a  slide 
valve  under  high  pressures,  and  when  worn,  can  be  replaced  with 
its  casings  by  duplicates,  furnished  at  a  nominal  cost,  with- 
out delay.  The  valves  are  proportioned  to  suit  the  requirements  of 
the  engine,  and  in  some  cases  have  double  or  treble  openings, 
supplying  steam  simultaneously. 

The  engine  can  be  reversed,  and  the  expansion  of  the  steam  con- 
trolled by  set  lever  e,  the  same  as  with  a  link  motion. 


The  high-pressure  cylinder. 
The  low-pressure  cylinder. 
The  steam  chest. 
The  receiver. 
The  exhaust  passage. 
The  high-pressure  piston, 
The  low-pressure  piston. 
The  piston  valve. 
The  valve  casing. 
The  reversing  lever. 
Crank-shaft. 


FIG.  83.— THE  WELLS  PATENT  COMPOUND  BALANCED  REVERSING  ENGINE. 


2io          Principal  Types  of  Yacht  Machinery. 

Balanced  weights,  balanced  momentum,  and  balanced  pressures 
are  qualifications  necessary  to  produce  a  durable  engine.  The 
wear  on  the  shaft  journals  and  their  boxes — the  most  difficult  parts 
to  repair — is  reduced  to  a  minimum.  What  little  wear  takes  place 
on  the  shaft,  due  to  its  weight  only,  will  be  evenly  distributed 
around  its  whole  circumference,  and  not  in  eccentric  form,  as  is  the 
case  in  other  engines,  where  it  produces  additional  friction, 
increased  wear,  and  knocking  in  the  boxes.  For  these  reasons  the 
effect  on  the  main  bearing  boxes  will  be  highly  advantageous. 

The  crank-shaft  is  constructed  from  a  block  of  hammered  steel, 
each  crank-pin  having  a  diameter  equal  to  the  shaft.  Piston  rods 
and  valve  stem  are  also  of  steel  and  packed  with  metallic  packing. 
Every  part  of  the  engine  can  be  oiled  while  running. 

The  low-pressure  cylinder  receives  its  steam  more  direct  than  in 
ordinary  compounds  and  hence  there  is  less  "drop"  in  pressure 
between  the  two  cylinders.  High  piston  speed  will  also  materially 
reduce  cylinder  condensation  and  increase  the  range  of  economical 
expansion.  Reduced  friction  on  bearings  is  a  further  source  of  sav- 
ing, as  the  following  comparison  of  performance  shows,  the  balanced 
engine  having  only  half  the  friction  due  to  pressure,  while  that  due 
to  momentum  is  entirely  removed,  so  that  the  bearings  will  not  heat. 


. 

Steeple  com- 
pound, single 
crank. 

Receiver  com- 
pound, cranks 
at  right  angles. 

Balanced  com- 
pound, cranks 
set  opposite. 

Mean  pressure    on   ist  crank- 
pin              

30,000  Ibs. 

I5,OOO 

Two  outside  pins 
7,500  each,  or  a 
total  of 

I5,OOO 

Mean   pressure   on    2d   crank- 

I5,OOO 

Middle  crank  pin 
I5,OOO 

Mean  pressure  on  main  bear- 
ings                    

3O,OOO 

3O,OOO 

6o,OOO 

6o,OOO 

30,000 

Compared  to  compounds  of  the  ordinary  type,  it  occupies  less 
space,  has  less  weight  and  fewer  parts.  The  difference  in  perform- 
ance of  single  cylinder  condensing  engine  and  compound  condensing 
engine  will  be  made  clear  from  the  following  figures: 


Principal  Types  of  Yacht  Machinery.  2 1 1 


Single  Cylinder. 

Compound. 

Size  of  engine 

16X16 

8  and  l6X  16 

Boiler  pressure 

loolbs 

100  Ibs 

dumber  of  expansions   

6 

6 

Force     exerted    on    piston    rod    at 
beginning  of  stroke 

Single  piston 
ii  tons 

Both  pistons  combined 
5  tons 

Force  at  end  of  stroke  

itf  tons. 

\y^  tons 

Variation  during  stroke 

Q3-/  tons 

•a  l2  tons 

Variation     of    temperature    due    to 
variation    of    force  or  pressure 
during   stroke  . 

176° 

C  High-pressure  cyl. 
\                  77° 

Low-pressure  cyl. 
99° 

That  is  to  say,  the  single  cylinder  is  subject  to  twice  the  variation 
in  temperature  and  three  times  the  variation  in  pressure. 

Boilers  would  compare  in  size  and  weight  and  feed  water  in 
pounds  required  per  H.  P.  per  hour: 


Horse  Power. 

10  to'as. 

40  to  80. 

100  up. 

Single  cylinder  exhausting  into  atmos- 
phere   

'    SO 

40 

•5-1 

Single  cylinder  exhausting  into  con- 
denser 

5O 

38 

28» 

Compound  cylinder  exhausting  into 
condenser.  . 

2* 

20 

18 

A  good  boiler  will  evaporate  30  to  40  Ibs.  of  feed  water  per  H.  P. 
per  hour.  The  Centennial  standard  is  30  Ibs.,  showing  that  the 
above  engines,  100  H.  P.  each,  would  require  boilers  as  follows: 


Single  Cylinder  Non-condensing      Single  Cylinder  Condensing. 

Compound   Condensing. 

100  H.  P. 
33  Ibs. 

100 

28 

IOO 

18 

300 
300 

800 

200 

800 

IOO 

30  Ibs.  )  3300 

30  )  2800 

30)  1800 

no  H.  P. 

93  H.  P. 

60  H.  P. 

2  1 2  Principal  Types  of  Yacht  Machinery. 

Showing  that  the  compound  requires  from  one-third  to  one-half  less 
boiler  capacity,  which  reduces  in  the  same  ratio  its  weight  and 
space,  and  the  fuel  consumed  per  H.  P. 

The  quadruple  expansion  engine  bears  the  same  relation  to  the 
compound  in  the  economical  use  of  steam  as  the  latter  does  to  the 
single-cylinder  engine.  To  obtain  greater  speed  of  vessel,  more 
power  more  economically  applied  must  be  employed,  without 
increasing  the  present  weight  of  machinery  or  the  space  it  occupies. 
This  can  only  be  attained  by  carrying  higher  steam  pressures  and 
increasing  the  number  of  expansions  without  undue  variation  in 
cylinder  temperature.  This  requires  four  cylinders.  The  objection 
to  this  type  of  engine  built  on  the  usual  plan  is  the  multiplicity  of 
parts,  greatly  increased  friction,  weight  of  engines,  and  space  they 
occupy.  The  balance  principle  eminently  fits  it  for  transmitting 
high  pressures  that  occupy  one-half  less  space,  or  no  more  room 
than  the  usual  fore  and  aft  compound  engine.  They  will  also  be 
less  in  weight,  while  the  weight  of  boiler  will  be  materially 
reduced. 

To  economically  transmit  80  H.  P.  by  the  Wells  system,  with  a 
boiler  pressure  of  175  Ibs.  and  a  piston  speed  of  600  ft.,  would 
require  a  boiler  capacity  sufficient  to  supply  a  cylinder  4  in.  diameter 
and  9  in.  stroke,  cutting  off  at  half-stroke. 

THE    COLT    DISC    ENGINES. 

The  Colt  Disc  Engine,  made  by  the  Colt  Patent  Fire  Arms 
Company,  is  an  excellent  device  which  has  been  supplied  to  many 
launches  and  small  yachts.  The  engine  belongs  to  the  self-inclosed 
class,  all  the  working  parts  being  contained  in  the  cylinder  casting, 
the  general  shape  being  such  as  to  suit  very  readily  the  form  of  the 
boat.  It  lies  so  low  as  to  admit,  if  required,  of  beinp'  floored 
over  so  as  to  economize  space,  access  to  it  being  very  seldom 
necessary,  as  the  lubrication  is  effected  by  oil  carried  in  by  the 
steam. 

In  general  construction  the  Disc  Engine  consists  of  six  parallel 
cylinders,  cast  in  a  circle  like  the  chamber  piece  of  a  revolver.  The 


C«3l 


214          Principal  Types  of  Yacht  Machinery. 

cylinders  (see  the  illustrations)  are  open  at  one  end  and  at  the  other 
abut  against  the  steam  chest,  C,  which  is  separated  from  the 
cylinders  only  by  a  plate  through  which  the  ports  are  cut.  The 
pistons,  A,  are  in  the  form  of  rams  or  plungers,  and  when  driven 
home  fill  up  the  cylinders. 

Facing  the  open  end  of  the  cylinders  is  a  disc,  B,  which  oscillates 
or  rolls  on  a  conical  bearing  at  E,  with  a  ball  and  socket  center. 
The  pistons  at  this  end  terminate  in  blunt,  conical  points  corres- 


FIG,  85. — SECTION  OF  CYLINDER  CASING. 

ponding  to  the  inclination  of  the  disc,  which  receives  its  motion  from 
the  pistons  as  they  press  against  it  one  after  another  in  rotation,  the 
steam  being  admitted  to  their  opposite  ends.  The  crank  G  occupies 
the  central  space  surrounded  by  the  cylinders  and  is  operated  by  a 
pin  F  carried  in  the  center  of  the  disc.  The  steam  distribution  is 
effected  by  an  annular  valve,  K,  surrounding  an  eccentric,  I,  inside 
the  steam  chest  and  driven  by  the  shaft  H,  which  passes  through  it. 
As  the  live  steam  is  confined  to  the  space  outside  the  annular  valve, 
nothing  but  exhaust  steam  comes  in  contact  with  the  shaft,  so  that 


2 1 6  Principal  Types  of  Yacht  Machinery. 

no  stuffing  box  is  necessary  where  the  latter  passes  through  the 
cover.  Of  course  the  pistons  are  single-acting,  the  return  stroke 
being  effected  by  the  disc  forcing  them  back  into  the  cylinders.  As 
a  natural  consequence  all  the  strains  are  continuous,  any  wear  that 
occurs  being  followed  up  by  the  bearing  surfaces,  and  no  pounding 
is  possible.  Besides  this,  in  nearly  all  cases  the  contact  between  the 
working  parts  is  a  rolling  one,  and  as  there  are  no  mechanical  con- 
nections anywhere,  there  is  a  constant  and  individual  motion  of  the 
parts,  the  result  being  that  while  the  friction  is  reduced  to  a 
minimum,  what  little  wear  there  is  is  distributed  uniformly  over  the 
entire  surface.  With  the  most  ordinary  care  on  the  part  of  the 
engineer  one  of  the  engines  will  run  for  several  seasons  without  the 
necessity  of  spending  a  dollar  for  repairs,  and  when  repairs  are 
eventually  needed  they  involve  tio  more  than  new  piston  ring  or  the 
renewal  of  some  of  the  bouches,  all  of  which  are  made  interchange- 
able. The  valve  arrangement  in  the  disc  engine  is  such  as  to  allow 
expansion  to  be  taken  advantage  of  to  a  very  great  extent  with  the 
result  of  unusual  economy  in  fuel  consumption. 

A  study  of  the  cuts  will  make  the  foregoing  clear.  For  that  pur- 
pose we  have  produced  a  section  through  the  engine,  in  a  fore  and 
aft  line,  another  across  the  eccentric  I,  showing  the  ports  for  steam 
and  exhaust  and  the  manner  in  which  they  are  opened  and  closed 
by  the  valve  ring  K,  and  a  third  cut  giving  general  interior  view 
with  back  cover  off,  and  the  disc  and  pistons  removed,  exhibiting 
the  positions  of  steam  ports  and  exhaust  passages  and  the  crank  G. 
Although  usually  arranged  to  cut  off  at  half  stroke,  a  simple  altera- 
tion in  the  valve  construction  enables  a  much  higher  degree  of 
expansion  to  be  obtained,  but  as  the  peculiar  form  of  the  engine 
renders  it  unusually  suitable  for  compounding,  this  method  is 
resorted  to  where  a  high  degree  of  expansion  is  desired.  In  the 
perspective  view  of  the  engine  the  thrust  collar  aft  of  the  crank 
shaft  bearing  and  the  lever  for  reversing  will  be  noted. 

Reversing  is  accomplished  by  throwing  the  bar  forward  or  aft. 
The  bar  is  forked  at  its  lower  end  and  grasps  a  collar  having  a  button 
traveling  in  a  spiral  slot  in  a  sleeve  connected  with  the  eccentric. 
By  moving  the  lever,  circular  motion  is  imparted  to  the  sleeve 


Principal  Types  of  Yacht  Machinery.  2 1 7 

of  the  eccentric,  which  is  thrown  to  the  opposite  side  of  the  crank, 
thus  causing  a  reverse  motion  of  the  engine. 

The  following  tables  are  interesting  as  a  guide  to  selecting  the 
power  and  corresponding  engine  required  for  boats  of  various  sizes, 
to  insure  satisfactory  performance: 


DIMENSIONS,    ETC.,    OF    MARINE    ENGINES.       (STANDARD.) 


Proportions  of  boat  and 

Effective  horse 

Diameter 

Pipe  connections. 

propeller. 

initial  pressure 

Boat 

Propeller 

Steam. 

Exhaust 

Length. 

Diam.      Pitch. 

In. 

In. 

In. 

Ft 

In.           In. 

4  to     5 

1  80  Ibs. 

II 

# 

I 

25 

18    X    18 

10    tO    12 

500  Ibs. 

15  /^ 

i 

Il/2 

35 

24   X    24 

20,    to    25 

i,i5olbs. 

20^ 

i* 

2 

45 

32   X    34 

35   to  40 

2,000  Ibs. 

25 

2 

50 

36  X   40 

45    to   50 

2,  800  Ibs. 

JK 

2]4 

60 

42    X    48 

65    to   75 

3,  800  Ibs. 

32^ 

1/2 

21/2 

75 

48    X    54 

Propellers  up  to  32  in.  diam.   are  two-bladed,   above    that  they 
have  three  blades. 

The   Colt  boilers  are  either  the   return    tube  or  vertical  kind, 
carrying  working  pressure  of  120  Ibs. 


SPECIFICATIONS    OF    RETURN    TUBE    MARINE    BOILERS. 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

Length  of  boiler  

Ft.    In. 

5     IO 

Ft.    In. 

6      4 

Ft.    In. 

7 

Ft.    In. 

7       6 

Diameter  of  boiler  

4       2 

4       6 

5 

5      4 

Length  of  furnace  and  tubes 

4         3 

4        Q 

5       5 

5     JI 

Diameter  of  furnace 

2         ^ 

2        6 

2        8 

a 

Number  of  tubes 

ce 

77 

qo 

75 

Diameter  of  tubes^                            . 

2 

2 

2 

2^ 

Grate  surface    (square  feet) 

7  87 

IO 

12 

15 

Heating  surface,  effective,  (square  feet)  
Size  of    disc  engine  )  Working  high  pressure 
for  which  suitable  )         "         low         " 

III 

5 
4 

162 

6 

5 

2O9 

6 

241 

7 

2 1 8  Principal  Types  of  Yacht  Machinery. 

SPECIFICATIONS    OF    VERTICAL    BOILERS. 


No.  i. 

No.  2. 

No.  3. 

Ft.        In. 

2           IO 

Ft.        In. 

3          2 

Ft.         In. 

3          8 

4          9 

5 

5          6 

Number  of  tubes   (all  2  in  )     

^5 

84 

93 

Grate  surface    (square  feet)  

4-74 

6.3 

8.29 

Heatinjr  surface   (square  feet)              

85 

139 

178 

Size  of  disc  engine  \  Working  high  pressure 
for  which  suitable  )                    low 

3 

2 

3 

4 

MACHINERY    FOR    SMALL    CRAFT. 

Safe  machinery,  as  automatic  in  action  as  possible,  and  of  low  first 
cost,  has  always  been  in  great  demand.  Recently  several  new 
methods  and  motors  have  come  into  prominence,  and  in  many 
respects  supply  the  necessities  of  a  growing  class  of  boat  owners  all 
over  the  United  States. 

The  Shipman  engine  and  boiler,  made  by  the  Shipman  Company, 
of  Boston,  are  well  calculated  to  meet  the  requirements  of  launches 
and  steam  dinghys,  owing  to  the  substitution  of  petroleum  for  coal 
as  fuel,  the  safety  of  the  boiler  and  the  self-acting  character  of  the 
machinery. 

The  general  operation  will  be  understood  from  the  descriptive 
illustration  of  the  "  Rochester  Model "  of  i  and  2  H.  P.  The 
boiler  is  of  the  sectional  or  pipe  variety,  each  tube  being  tested  to 
400  Ibs.  per  square  inch,  and  the  completed  boiler  the  same. 
Although  the  boiler  is  practically  inexplosive,  it  is  provided  with  a 
regular  safety  valve.  A  coil  pipe  heater  on  top  delivers  the  water  to 
the  boiler  at  180  deg.,  the  supply  being  regulated  by  the  float  in  the 
float  chamber  connecting  with  valve  of  pump,  which  opens  and 
closes  automatically  and  keeps  a  uniform  volume  of  water  in  the 
boiler  without  intervention  of  the  engineer. 

Kerosene  of  no  deg.  test  serves  for  fuel,  requiring  small  storage 
room,  the  services  of  a  fireman  and  the  dirt  from  coal  being  avoided. 
The  fire  is  made  by  the  pressure  of  steam  flowing  through  an 
atomizer,  which  throws  the  kerosene  in  a  very  fine  spray  into  the 


H 


FIG.  83. — ROCHESTER  MODEL. 


A.  Diaphragm. 

B.  Pipe  connecting  diaphragm  to  atomizer. 

C.  Atomizer. 

D.  Oil  tank. 

E.  Lamp  or  torch. 

F.  Air  pump  handle. 

G.  Pipe  connecting  air  pump  to  the  boiler. 
J.  Blow-off  valve. 

K.  The  drain  pipe  from  exhaust  steam  heater. 

L.  The  pipe  connecting  feed  water  pump  to 

the  heater. 

M.  Drip  pipe  from  the  exhaust  steam  heater. 

N.  Exhaust  steam  pipe. 

O.  Steam  gauge. 


P.     Pop  or  safety  valve. 

Q.     Water  glass. 

R.     Float  chamber. 

S.     Throttle  valve. 

T.     Swift  lubricator  to  the  cylinders. 

U.     Feed  water  pump. 

V.     Strainer  to  feed  water  pump. 

W.     Brass  cylinder  cap. 

X.     Shield  to  the  governor. 

Y.  Steam  valve  eccentric  connected  to  gov- 
ernor. 

Z.  The  perpendicular  rod  operated  by  float 
in  float  chamber  to  cut  off  the  supply  of 
water  to  the  feed  water  pump. 


[219] 


22O          Principal  Types  of  Yacht  Machinery. 

fire-box  and  gives  an  intense  blast  without  the  use  of  wicks.  The 
combustion  is  perfect,  and  the  highest  results  are  obtained.  The 
"  diaphragm  "  controls  the  fire  so  that  a  definite  pressure  can  be 
carried. 

The  oil  tank  in  front  of  boiler  holds  two  gallons.  This  tank  has 
a  water  space  between  the  oil  and  fire-box,  and  this  space  is  filled 
with  water  from  the  feed  water  supply,  and  then  pumped  into  the 
boiler.  In  this  way  there  is  a  constantly  changing  jacket  of  water 
three-fourths  of  an  inch  thick  in  front  of  the  oil,  making  it  impos- 
sible to  heat  it. 

The  feed  pump  is  of  brass  with  lift  and  force  valves.  The  plunger 
is  connected  to  the  main  shaft  by  an  eccentric,  and  is  constantly  in 
operation  while  the  engine  is  in  motion.  In  connection  with  the 
float  regulator,  it  keeps  up  just  the  right  feed. 

The  automatic  governor  increases  or  decreases  the  opening  of  the 
steam  ports,  and  preserves  a  uniform  speed  with  varying  load. 
Cylinder  has  a  self  oiler,  and  the  connecting  rod  is  also  oiled 
automatically.  The  piston  has  adjustable  packing  rings. 

The  marine  boiler  is  of  wrought  iron  and  with  the  machinery  is 
operated  on  the  principles  explained  for  the  stationary  engine.  Two 
eccentrics  with  link  motion  and  reversing  gear  are  supplied  to  all 
yacht  engines.  About  half  a  gallon  of  kerosene  is  required  per 
H.  P.  per  hour,  although  smaller  consumption  is  reported.  This 
makes  the  cost  about  3^  to  4  cents.  The  engines  have  i,  2,  3  or  4 
H.  P.  A  launch  of  25  ft.  length  requires  about  2  H.  P.  for  speed  of 
eight  miles. 

The  kerosene,  after  being  thrown  into  spray  by  the  pressure  of 
the  air,  before  starting  is  ignited  in  the  fire-box  by  the  "torch." 
There  is  little  or  no  smoke.  The  fire,  after  the  engine  is  running,  is 
automatically  regulated  by  the  "diaphragm."  As  the  pressure  of 
the  steam  rises  to  the  point  at  which  the  diaphragm  has  been  set  by 
a  screw,  say  ioolbs.,  the  diaphragm  is  gradually  raised,  carrying 
with  it  a  valve  which  cuts  off  the  passage  of  steam  to  the  atomizer 
and  thus  reduces  the  fuel  supply.  If  the  pressure  reaches  100  Ibs. 
the  valve  entirely  cuts  off  the  supply  of  steam  and  the  flame  shrinks 
to  correspond  The  moment  the  pressure  again  falls  below  100  Ibs. 


Principal  Types  of  Yacht  Machinery.  221 

the  valve  is  released,  steam  spurts  through  the  atomizers  carrying 
the  oil,  and  the  spray  is  freshly  ignited  by  the  torches  kept  burning 
at  the  side  of  the  atomizers. 


FIG.  89. — SHIPMAN  MARINE  ENGINE. 


So  nice  is  this  action  that  adding  a  single  lath  to  the  engine's 
"  load  "  will  make  an  instantaneous  and  perceptible  difference  in  the 
fire.  If  on  the  other  hand  the  entire  load  on  the  engine  is  suddenly 


[222] 


Principal  Types  of  Yacht  Machinery.  223 

removed,  and  the  engine  held  by  a  brake,  the  pressure  will  not  rise 
more  than  three  pounds,  so  quickly  is  the  flame  choked  off. 

Under  the  U.  S.  laws,  quoted  in  a  previous  chapter,  all  boilers 
which  make  steam  must  be  inspected  and  proper  papers  obtained, 
and  no  boiler  made  wholly  or  in  part  of  cast  iron  will  be  permitted. 
The  Board  of  Supervising  Inspectors  of  the  United  States,  at  the 
annual  meeting  in  Washington,  January,  1887,  tested  the  Shipman 
engine  and  boiler  and  approved  the  same.  A  "special  license"  to 
run  the  machinery  will  be  granted  to  any  person  familiar  with  its 
operation,  and  the  same  person  can  obtain  a  *'  special  license  "  as 
pilot.  The  address  of  the  local  inspector  can  be  obtained  at  the 
nearest  custom  house.  Write  to  him,  giving  name,  length,  width 
and  depth  of  boat  and  where  to  be  used,  also  manufacturer's  num- 
ber of  engine.  The  inspector  will  then  test  the  boiler  by  hydraulic 
pressure  and  issue  a  permit.  If  the  boat  is  to  be  used  on  inland 
lakes  or  rivers  not  under  control  of  the  United  States  inspection 
laws,  no  inspection  or  license  is  necessary. 

OSCILLATING    ENGINES. 

The  only  oscillating  engine  applied  to  steam  launches  in 
America  is  the  Kriebel  valveless  engine,  built  by  Rice  &  Whitacre, 
of  Chicago.  This  engine  has  no  connecting  rod  and  crosshead, 
the  piston  rod  actuating  the  crank  without  intervening  parts,  the 
oscillation  of  the  cylinder  providing  for  the  lateral  travel  of  the 
crank-pin.  The  motion  of  the  cylinder  also  serves  to  open  and 
close  the  steam  and  exhaust  ports,  as  will  appear  from  the  sectional 
cut  of  the  engine. 

The  engine  frame,  OO,  is  made  in  one  piece  and  has  boxes  on 
each  side  to  receive  the  crank  shaft,  M,  and  the  solid  trunnions,  E, 
which  project  at  right  angles  from  the  upper  head  of  the  cylinder 
and  on  which  the  cylinder  is  supported  and  pivoted.  The  piston, 
H,  is  connected  by  the  piston  rod,  I,  to  the  crank-pin,  L,  and  the 
three  are  always  in  a  straight  line,  consequently  as  the  piston 
moves  up  and  down,  the  cylinder  vibrates  back  and  forth  on  the 
trunnions. 


224  Principal  Types  of  Yacht  Machinery. 

The  valve,  D,  is  a  hollow,  cylindrical  casting  inclosed  in  a  casing, 
A,  attached  to  the  engine  frame.     The  bottom  of  the  valve  has  a 


A. T. SEARS 

FIG.  91. — SECTION  OF  KKIEBEL  ENGINE. 

smooth  concave  surface,  while  the  upper  end  of  the  cylinder,  F,  has 
a  smooth  convex  surface.     The  two  surfaces  make  a  perfect  joint 


Principal  Type*  of  Yacht  Machinery.  225 

and  any  wear  that  occurs  is  automatically  taken  up  by  springs,  U, 
coiled  around  bosses  above  the  valve. 

The  steam  and  exhaust  pipes,   S  and  T,  connect  with  two  brass 


FIG.  92. — THE  KRIEBEL  OSCILLATING  LAUNCH  ENGINE. 

tubes,  R  and  R1,  which  are  screwed  into  the  valve  and  communi- 
cate with  the  valve  ports,  X  and  QQ1.  There  are  two  cylinder  ports, 
P  and  P1,  which  open  into  the  top  and  bottom  of  the  cylinder.  As 


226          Principal  Types  of  Yacht  Machinery. 


the  cylinder  vibrates  back  and  forth  on  the  trunnions  the  cylinder 
ports  alternately  take  steam  from  the  central  valve  port,  X,  and 
exhaust  through  the  ports  Q  and  Q1.  In  the  reversing  engines,  the 
direction  of  the  steam  in  the  tubes  can  be  changed  so  the  cylinder 
ports  will  either  take  steam  from  the  port  X  and  exhaust  through 
the  ports  Q  and  Q1  as  above,  or  else  take  steam  from  Q  and  Q1  and 
exhaust  through  X,  and  thus  reverse  the  engine. 

The  piston  rod  has  a  long  stuffing  box,  N.  The  upper  ends  of 
the  tubes,  R  and  R1,  are  received  by  fixed  stuffing  boxes,  C. 
B  represents  a  counterbalance,  which  is  bolted  to  the  cranks  of 
engines  with  5  X  6  in.  cylinder  and  upward. 

The  reversing  valve  on  top  answers  also  as  a  throttle,  as  by 
moving  the  lever  to  a  central  position,  the  steam  and  exhaust  ports 
are  closed  and  the  engine  stops.  There  is  of  course  a  saving  of 
friction  and  weight  over  engines  of  the  ordinary  vertical  type  having 
eccentrics,  link  gear  and  slide  valve. 


Piston. 

Horse  power. 

Floor  space 

Height. 

Weight. 

Diameter.     Stroke. 

With  80  to  nolbs. 
boiler  pressure. 

Occupied  by 
engine  bed. 

Over  all. 

Engine  and 
fixtures. 

Inches. 

Inches. 

Feet.       Inches. 

Pounds. 

3%    X    4 

2  to    3 

13   X   12 

2              6 

1  60 

4        X    A 

3  to    4 

15   X    15 

2               7 

200 

5        X    6 

6  to    8 

16  X  18 

3           6 

400 

6        X    7 

8  to  10 

19  X  20 

3          10 

560 

6^    X    9 

10  to  12 

22  X   24 

4           3 

900 

7K    X    9 

12  to  16 

22   X   24 

4           3 

950 

Principal  Types  of  Yacht  Machinery.  227 


KANE'S    PORCUPINE    BOILER. 

The  engine  is  a  simple  single  cylinder  with  taper  balance  plug 
valve.  Five  horse  power  has  a  diameter  of  cylinder  5  in.,  stroke 
5  in  Kane's  Porcupine  Boiler  is  built  of  lap  weld  boiler  tubes. 
The  five  horse  power  boiler  has  118  tubes,  2 in.  in  diameter  by  loin. 


FIG.  93. — KANE'S  PORCUPINE  BOILER. 


228  Principal  Types  of  Yacht  Machinery. 

long,  tapped  into  a  center  column  which  is  7  in.  diameter  by  38  in. 
long,  like  the  quills  of  a  porcupine.  Within  the  center  column  of 
water  is  a  fire  tube  which  is  3^2  in.  in  diameter  and  38  in.  long, 
expanded  in  the  heads  of  center  column.  This  boiler  has  5 8  sq.ft. 
of  heating  surface.  Ordinary  kerosene  oil  of  from  no  to  150  test 
is  used  for  fuel.  Distillate  oar  residual  oil  can  also  be  used,  and  is 
obtained  at  any  refinery  for  3  or  4  cts.  per  gallon  and  is  found  to  be 
very  economical.  The  amount  used  averages  ^  gallon  per  horse, 
power  per  hour,  but  this  can  be  materially  reduced  in  larger  boilers. 
The  oil  is  stored  in  a  galvanized  iron  tank,  in  the  bow  or  stern, 
and  is  conveyed  from  there  by  %  in.  iron  pipe  to  near  the  boiler, 
and  thence  by  a  iV  in.  pipe  to  atomizer.  The  oil  is  drawn  from  the 
tank,  atomized  by  jet  of  super-heated  steam,  mixed  with  sufficient 
air  for  combustion  and  forced  into  a  heated  retort.  The  mixture 
of  oil  and  steam  is  decomposed  into  its  componate  gases,  and 
conveyed  to  a  burner  under  the  center  of  boiler  where  they  burn 
with  an  intensely  hot  flame,  without  smoke  or  disagreeable  noise. 
No  torch  is  required  to  keep  the  fire  lit.  The  burner  is  not  liable 
to  become  clogged,  and  the  pitching  of  the  yacht  does  not  affect 
the  fire.  The  supply  of  fuel  is  regulated  by  an  upright  lever  which 
controls  the  flow  of  oil  and  regulates  the  combustion.  By  turning 
it  to  the  left  more  oil  can  be  obtained,  and  to  the  right  less  oil. 


Principal  Types  of  Yacht  Machinery.  229 


NAPHTHA     LAUNCHES. 

One  of  the  most  satisfactory  and  serviceable  of  motors  recently 
introduced  to  take  the  place  of  steam  in  small  craft,  is  the  machin- 
ery operated  by  naphtha,  as  built  by  the  Gas  Engine  and  Power 
Company,  of  New  York.  No  steam  is  used  in  this  motor,  no 
licenses  of  any  sort  are  required,  and  explosion  is  practically  impos- 
sible. The  motor  is  very  compact  and  takes  up  little  space.  The 
weight  is  very  small,  a  2  H.  P.  engine  weighing  only  200  Ibs;  a  4 
H.  P.  300  Ibs.,  and  an  8  H.  P.  only  600  Ibs.,  which  is  about  one-fifth 
that  of  ordinary  steam  machinery  of  equal  power.  Two  minutes 
suffice  to  get  under  full  headway.  Reversing  is  instantaneous  and 


FIG.  94. — NAPHTHA  LAUNCH,  18  FT.  LONG,  2  H.  P. 

no  attention  is  needed  after  the  motor  is  stopped  and  the  boat 
secured  to  the  dock  or  hoisted  to  the  davits  of  a  yacht. 

The  machinery  is  always  clean,  as  there  is  neither  dirt,  ashes  nor 
water.  An  18  ft.  launch  with  2  H.  P.  engine  will  carry  from  six  to 
ten  persons,  and  a  21  ft.  boat,  with  3  H.  P.  engine,  from  ten  to 
fifteen  passengers  at  a  speed  from  6  to  8  miles  an  hour,  and  a  cost 
of  six  cents  per  hour.  A  30  ft.  launch  with  4  H.  P.  will  seat  twenty- 
five  persons. 

The  operation  of  the  engine  is  briefly  described  as  follows:  A 
copper  tank  in  the  bow  of  the  boat  is  filled  with  76  deg.  deodorized 
naphtha  through  a  tap  screw  on  top.  The  tank  will  hold  from  30  to 
60  gallons,  according  to  size  of  boat.  A  2  H.  P.  engine  will  con- 
sume about  3  quarts  per  hour,  and  a  4  H.  P.  engine  about  5  quarts. 


230  Principal  Types  of  Yacht  Machinery. 

The  vapor  which  accumulates  in  the  tank  is  pumped  by  a  few 
strokes  to  the  burner  in  the  retort  or  chimney  containing  a  coil  of 
pipe.  A  flame  from  a  lamp  or  torch  ignites  the  vapor  as  it  escapes 
from  the  burner.  This  flame  supplies  the  heat  for  evaporating  the 
naphtha  itself,  which  is  next  pumped  from  the  bottom  of  the  tank  into 
the  coil  of  the  retort.  Very  little  heat  is  required  to  volatilize  the 
naphtha  in  the  coil,  from  which  it  escapes  into  the  lower  casing  con- 
taining single-acting  cylinders  operating  the  crank  shaft  and 


FIG.  95. — LAUNCH  SWUNG  TO  YACHT'S  DAVITS. 


automatic  feed.  After  expanding  in  these  cylinders  the  exhaust 
vapor  passes  into  a  condensing  pipe  and  is  returned  to  the  tank  to  be 
used  over  again.  The  flame  is  supplied  as  needed  by  drawing  off 
a  small  amount  of  the  vapor  from  the  coil,  and  the  only  loss  of 
naphtha  is  represented  by  the  vapor  thus  burned. 

To  start  the  engine:  Light  alcohol  lamp  A,  and  set  on  rest  plate, 
with  tube  inserted  at  bottom  of  retort;  turn  air  valve  B  from  left  to 
right;  give  air  pump  E  sufficient  number  of  strokes  to  force  gas 


Principal  Types  of  Yacht  Machinery.  231 

from  tank,  through  outlet  pipe  to  burner,  where  flame  from  lamp 
ignites  it  and  so  heats  retort.  Use  air  pump  one  to  two  minutes  in 
warm  weather;  but  in  cold  weather  much  longer,  as. gas  generates 
very  slowly  in  the  tank  then.  Open  wide  naphtha  valve  D,  and  give 
five  to  ten  strokes  of  naphtha  pump  F,  which  pumps  naphtha  from 
tank  in  bow  to  retort  on  top  of  engine,  and  if  retort  has  been  suffi- 
ciently heated,  the  pressure  will  at  once  be  indicated  on  gauge. 
Then  open  injector  valve  C,  which  supplies  fuel  to  burner;  after 


FIG.  96. — 30  FT.  LAUNCH,  WITH  FOUR  HORSE  POWER  ENGINE. 


which  turn  reverse  wheel  G  from  right  to  left,  or  vice  versa,  a  few 
times  until  engine  will  run  itself.  To  increase  pressure,  after  engine 
is  started,  give  a  few  strokes  with  naphtha  pump  F  and  open  wide 
injector  valve  C.  Regulate  both  speed  and  pressure  by  injector 
valve  C — opening  to  increase,  and  closing  to  reduce  speed.  To  go 
ahead  turn  reverse  wheel  G  to  left;  to  back,  turn  wheel  to  right. 
You  can  reverse  instantly,  and  at  full  speed.  Lamp  can  be  taken 
out,  extinguished,  and  set  on  rest  plate  with  tube  outside  as  soon  as 
engine  is  running.  H  indicates  safety  valve.  When  landing  it  is 


232  Principal  Types  of  Yacht  Machinery. 

only  necessary  to  close  injector  C  and  naphtha  valve  D,  fasten  your 
boat,  and  no  further  attention  is  required. 

The  "  air  pump  "  draws  the  gas  from  the  tank  to  the  burner  and 


FIG.  97. — NAPHTHA  LAUNCH  ENGINE.  , 


also  to  a  whistle,  by  turning  valve  B  from  right  to  left.  The  naphtha 
valve  should  be  left  wide  open  to  allow  free  circulation.  For  the 
lamp  A  use  alcohol  only. 


XI. 

THE    DESIGN    OF    HULLS. 


LITTLE  that  is  precise  can  be  laid  down  for  governing  the 
design  of  steam  yacht  hulls.  The  first  requisite  is  that  the 
displacement  at  a  given  draft  of  water  shall  be  equal  to  weight  of 
hull,  motive  power  and  equipment  combined,  with  ballast  added 
where  such  is  to  be  carried.  In  the  majority  of  cases  ballast  is  not 
necessary  to  a  steam  yacht,  for  the  weight  of  machinery,  fuel  and 
stores  stand  in  its  stead.  But  there  are  occasions  where  ballast  in 
addition  is  justifiable.  Coal  cannot  be  stowed  low,  the  bunkers 
reaching  up  to  deck  to  provide  the  necessary  room,  and  overhead 
cylinders  will  contribute  to  a  high  general  center  of  gravity, 
especially  if  the  rig  and  deck  weights  be  large  also.  The  resulting 
top-heaviness  can  be  met  in  the  design  by  giving  the  boat  more 
beam,  in  which  case  she  would  be  stiff  enough  without  ballast. 
But  the  architect  may  not  wish  to  resort  to  such  correction,  for  he 
may  prefer  a  narrower  and  deeper  model  to  attain  other  ends  in 
view.  Knowing  that  weight  or  displacement  in  itself  is  not  a  true 
measure  of  resistance,  but  that  larger  displacement  and  cross- 
sectional  area  can  be  driven  upon  correspondingly  smaller  beam 
with  like  power,  owing  to  the  lesser  "wave-making"  tendencies  of 
narrower  hull,  the  architect  may  elect  to  retain  small  beam  and 
correct  want  of  stability  by  adding  to  the  displacement  a  certain 
amount  for  an  allowance  of  ballast.  The  result  will  be  a  model  of 


234  The  Design  of  Hulls. 

no  greater  resistance  than  the  wider  boat  of  more  beam  and  less 
displacement.*  At  the  same  time,  sufficient  stability  will  be 
insured  by  a  low  center  of  gravity  instead  of  depending  upon  the 
high  meta-center  due  to  large  beam. 

The  extra  depth,  weight  and  easy  form  are  by  some  designers 
preferred  for  good  sea-going  qualities  and  easy  behavior.  The 
weight  of  ballast  cannot  in  such  cases  be  put  into  greater  weight 
of  engines  and  fuel,  because  such  addition  would  be  in  the  wrong 
place  for  stability  and  might  aggravate  the  evil  of  top-heaviness. 
As  a  rule,  however,  steam  yachts  are  planned  to  do  without  ballast. 
The  great  majority  can  afford  to  overlook  the  highest  sea-going 
qualities,  particularly  along  the  American  coast,  where  smooth-water 
navigation  and  short  runs  outside  from  port  to  port  in  reasonably 
fair  weather  preponderate  greatly. 

No  directions  for  proportions  of  hull  can  be  quoted.  In  general, 
five  beams  to  waterline  length  with  such  depth  as  the  displacement 
calls  for,  will  serve  the  wants  of  the  cruising  steamer.  For  high 
speed,  the  ratio  between  breadth  and  length  is  increased.  Ex- 
perience as  well  as  inference  teaches  that  the  longest  aud  narrowest 
hull  is  the  form  of  least  resistance,  and  the  only  restriction  is  the 
demand  for  beam  enough  to  bring  about  the  requisite  stability. 
Thus,  the  racing  shell-boat,  propelled  by  oars,  is  not  built  wide  and 
shallow  with  a  saucer  section,  but  on  the  contrary,  the  cross  section 
is  almost  semi-circular  and  the  width  of  the  boat  narrowed  down  to 
the  utmost  practicable,  the  only  limit  being  the  width  necessary  to 
seat  the  man  pulling  the  oars.  Similar  forms  would  be  followed  in 
the  hulls  of  high  speed  steamers,  but  for  the  fact  that  such  forms 
will  capsize,  unless  sustained  by  the  application  of  extraneous 
support,  which  in  the  racing  shell-boat  is  derived  from  the 
blades  of  > the  oars  resting  on  the  surface  of  the  water  with  their 
handles  passing  through  rowlocks  closed  across  the  top,  acting  as 
long  supporting  levers  rigged  out  on  each  side  of  the  boat.  Such 
assistance  being  impossible  in  a  steam  yacht,  more  beam  is  taken 
in  proportion  to  length,  so  that  the  vessel  will  be  able  to  float  on 
her  own  bottom. 

*  See  "Small  Yachts,"  pages  46  and  55.     (Forest  and  Stream  Publishing  Co.,  New  York.) 


The  Design  of  Hulls.  235 

There  is  also  one  other  consideration  governing  the  choice  of  beam 
in  proportion  to  length.  This  is  a  physical  rather  than  a  theoretical 
restriction.  As  the  length  is  increased,  the  "lines"  of  the  hull  will 
of  course  become  finer  and  more  favorable  to  speed.  But  the 
increase  in  length  is  also  accompanied  by  an  increase  of  weight  of 
hull  and  we  have  to  draw  more  and  more  upon  the  displacement  to 
float  this  weight,  which  is  equivalent  to  robbing  the  driving  power  of 
an  equal  amount.  While,  therefore,  form  is  being  refined  for  speed 
on  the  one  hand,  we  are  on  the  other  hand  diminishing  the  possi- 
bilities for  driving  power. 

Now,  up  to  a  certain  not  well  defined  point,  it  is  found  in  practice 
that  more  is  gained  by  refining  the  hull  than  is  lost  by  the  restriction 
to  driving  power.  Up  to  that  point,  it  is  advantageous  to  high 
speed  to  narrow  the  hull.  But  after  this  point  is  once  passed,  a 
further  refinement  of  hull  is  no  longer  beneficial  to  speed,  and  the 
loss  in  driving  power  would  make  itself  evident  by  a  loss  in  speed. 
The  explanation  of  this  limit  to  narrowing  beam  is  simple  enough. 
When  the  critical  point  mentioned  has  been  reached,  the  lines  of 
the  hull  will  already  be  extremely  sharp.  A  further  diminution  of 
the  beam  will  affect  the  general  angle  of  entrance  and  run  only 
very  slightly,  while  the  extra  length  will  add  very  perceptibly  to 
the  weight  of  hull,  so  that  we  would  be  losing  in  the  weight  of 
engine  faster  than  the  gain  due  to  the  small  additional  refinement 
of  hull. 

Just  where  the  limit  to  fining  of  hull  really  lies,  cannot  be 
answered  except  through  experiment.  The  limit  will  vary  more  or 
less  with  the  form  of  the  hull  as  a  whole  and  the  character  of  its 
lines,  and  to  that  extent  must  remain  a  matter  of  judgment  in  each 
case.  Stated  broadly,  the  builders  of  high  speed  yachts  adhere  to 
seven  and  eight  beams  to  waterline  length,  and  sometimes  even  go 
beyond.  These  proportions  seem  fully  justified  by  the  well  known 
tendency  of  beam  to  throw  off  waves,  representing  a  loss  in  power 
As  speed  is  increased,  the  five  beams  of  the  seven  to  ten  knot 
cruiser  must  give  way  to  much  narrower  bodies  in  order  that  they 
may  be  driven  at  fifteen  to  twenty  knot  rates. 

The  depth  will  be  regulated  by  the  beam  and  contour  of  midship 


236  The  Design  of  Hulls. 

section,  since  the  required  displacement  upon  fixed  length  and 
breadth  depends  in  the  main  upon  the  area  of  the  midships. 

The  high  speed  torpedo  boats  of  most  recent  European  construc- 
tion have  from  eight  to  nine  and  a  half  beams  to  length,  the  latter 
being  the  extreme  beyond  which  present  experience  shows  no 
further  profit. 

The  character  of  cross  section  varies  according  to  the  views  and 
purposes  of  the  designer.  Some  boats  are  given  a  great  deal  of  dead 
rise  to  the  floor,  with  flare  to  the  topsides  above  water.  Others  are 
distinguished  by  flat  floor  and  low  bilge,  particularly  where  the 
draft  is  to  be  small.  The  illustrations  throughout  these  pages 
supply  ample  information  on  this  head. 

Fore-and-aft  waterlines  follow  no  specific  rule.  Wide  boats  need 
some  hollow  in  the  ends  to  produce  sharp  entrance.  Narrow  boats 
are  so  fine  from  their  dimensions  that  the  entrance  is  frequently 
wedge  shape  or  even  parabolic  in  character.  Wide  boats  need 
greater  length  of  entrance  than  narrow  craft,  as  the  beam  has  to  be 
"conciliated."  In  narrow  high-speeds  the  length  of  run  is  increased 
to  insure  complete  closing  of  the  wake  and  avoid  unbalanced 
"head"  at  the  bow. 

Towing  competitive  models  through  tanks  with  adequate  instru- 
ments for  correct  notation  is  the  only  method  upon  which  the 
designer  can  depend  for  positive  forecast  of  speed  performance. 


LIGHTS    ON    STEAM    YACHTS. 

Reference  has  been  made  in  the  chapter  on  Sailing  Rules  to  the 
decision  in  the  case  of  the  Yosemite  vs.  Vanderbilt,  the  judge 
deciding  that  steam  yachts  should  carry  the  lights  prescribed  for 
inland  navigation.  The  following  correspondence  in  connection 
with  this  case  will  explain  itself.  Unfortunately  it  leaves  the  ques- 
tion in  a  contradictory  state,  though  sound  practical  sense  is 
certainly  on  the  side  of  the  Treasury  Department  decision  as  given 
below : 

TREASURY  DEPARTMENT,  WASHINGTON,  D.  C.,  April  9,  1887. 
Capt.  John  G.  Hulphers,  Steamer  IVyanoke,  Richmond,   Va.  : 

SIR:  I  am  in  receipt  of  your  letter  of  the  8th  inst.,  with  newspaper  clipping- 
enclosed,  containing  a  synopsis  of  the  recent  decision  of  Judge  Andrews,  of  the 
Supreme  Court  of  the  State  of  New  York,  in  the  Vanderbilt- Yosemite  case, 
wherein  it  is  held,  in  substance,  that  an  ocean-going  steamer  should,  when  navi- 
gating inland  waters,  change  the  lights  required  by  Rule  II.,  Sec.  4,233  Revised 
Statutes,  to  those  required  upon  harbor,  lake  and  inland  steamers,  by  Rule  VII.,  of 
the  same  statute,  and  you  ask  whether  or  not,  in  accordance  with  Judge  Andrews's 
decision,  you  are  to  change  the  lights  of  your  vessel,  an  ocean-going  steamer, 
when  she  is  navigating  inland  waters. 

In  reply,  I  have  to  inform  you  that  this  case  having  been  previously  presented 
to  me  by  another  correspondent,  the  subject  was  referred  to  the  Solicitor  of  the 
Treasury  for  an  opinion  ' '  whether  officers  of  the  Government  were  hereafter  to 
administer  the  laws  in  accordance  with  Judge  Andrews's  decision."  To  which 
the  Solicitor  has  replied,  in  letter,  dated  April  6,  addressed  to  the  Secretary  of  the 
Treasury,  and  now  on  file  in  this  office,  "that  officers  of  the  Government,  in 
the  administration  of  the  navigation  laws  of  the  United  States,  should  be 
governed  by  the  laws  of  the  United  States,"  meaning  as  understood  by  this 
office,  that  ocean-going  steamers,  even  though  such  steamers  may  be  incidentally 
navigated  in  inland  waters  or  harbors,  and  notwithstanding  the  decision  referred 
to,  must  carry  the  lights  provided  in  Article  3,  "  Revised  International  Rules  and 
Regulations  for  Preventing  Collisions  at  Sea,"  approved  March  3,  1885. 

JAS.  A.  DUMONT, 

Supervising  Inspector. 


USEFUL    INFORMATION. 


WATER. 

i  gallon  U.  S.  Standard  contains  231  cu.  in.  and  weighs  8^  Ibs. 
i  cu.  ft.  of  water  measures  1%  gallons  and  weighs  62.5  Ibs. 
i  cu.  ft.  of  salt  water  weighs  64.3  Ibs. 

(  2.30  ft.  high  =  i  Ib.  per  sq.  in. 
Pressure  of  a  column  of  water  at  60°  tempr.  -j  1. 129  ft.  high  =  i  in.  of  mercury. 

(  33.86ft.  high  =  atmospheric  pressure. 

A  cubic  inch  of  water,  evaporated  under  ordinary  atmospheric  pressure,  is  con- 
verted into  i, 700 cu.  in,,  or  in  round  numbers,  i  cu.  ft.,  and  gives  a  mechanical 
force  equal  to  raising  2, 200  Ibs.  i  ft.  high. 

The  height  of  a  column  of  fresh  water  equal  to  a  pressure  of  i  Ib.  per  sq.  in.  is 
usually  computed  at  2  ft. ,  thus  allowing  for  ordinary  friction. 

To  compute  the  horse  power  necessary  to  raise  water  to  any  given  height, 
multiply  the  total  weight  of  the  column  of  water  in  pounds  by  the  velocity  in  feet 
per  minute  and  divide  by  33,000,  to  which  should  be  added  about  25  per  cent,  for 
friction,  etc. 

Water  at  high  temperature  cannot  be  raised  to  any  considerable  distance  by 
suction,  as  the  vapor  discharged  by  water  so  heated  follows  the  receding  piston  of 
the  pump,  and  resists  the  entrance  of  the  water,  and  is  elastic  enough  to  be  com- 
pressed and  distended  by  the  action  of  the  piston  without  being  displaced,  thus 
defeating  the  service  of  the  pump.  Water  at  boiling  temperature  must  flow  to  the 
pump. 

Sea  water  boils  at  213.2°    )  under  atmosphere  pressure,  and 
Fresh  water  boils  at  212°    J      at  124°  less  in  a  vacuum. 

Every    cubic    foot    of  water  evaporated   in   a  boiler   at   the  pressure  of   the 
atmosphere  will  heat  2,ooocu.  ft.  of  space  to  an  average  temperature  of  75°. 
i  sq.  ft.  of  steam  pipe  will  warm  200  ft.  of  space. 

FUEL. 

i  Ib.  of  coal  will  evaporate  from  7  to  10  Ibs.  of  water. 

i  Ib.  of  dry  pine  wood  will  evaporate  from  4  to  5  Ibs.  of  water. 

I  ton  of  anthracite  coal  requires  a  space  of  42  cu.  ft. 

I  ton  of  bituminous  coal  requires  a  space  of  44  cu.  ft. 

150-35  cu.  ft.  of  air  are  required  for  the  combustion  of  i  Ib.  of  coal. 


Useful    Information. 


239 


WEIGHT    OF    VARIOUS    SUBSTANCES. 


Cubic  foot. 

Cubic  inch. 

Cubic  foot. 

Cubic  inch. 

Cast  Iron  
Wrought  Iron.  . 
Steel 

Lbs. 
450.55 
489-65 
480  8 

Lbs. 
.2607 
.2816 

28^4 

White  Pine  
Yellow  Pine  
White  Oak 

Lbs. 
29.56 
33.81 
je  .2 

Lbs. 
.0171 
.019 
O26 

Copper 

cec 

.^,UJ-(. 

.^2118 

Live  Oak 

7O. 

.O4O 

Lead  .      . 

7O8.75 

.41015 

Sand  

05. 

Brass 

ea7   71: 

qH2 

!Clay 

jac 

WEIGHT   OF   SHEET  AND    PLATE   IRON   PER   SQUARE   FOOT. 


No.  B.  Wire  Gauge 

16 

II 

7 

a 

i 

Thickness  . 

JL- 

u 

A 

i/ 

-h 

^ 

A 

Pounds  

2.5 

t 

7.6 

10 

12.5 

1C  .2 

17.7 

TENSILE    STRENGTH. 

Weight  or  force  necessary  to  tear  asunder  i  sq.  in.  in  pounds  bar  iron,  60,000; 
cast  iron,  15,000;  wrought  copper,  34,000;  steel,  120,000;  copper  wire,  61,000; 
iron  wire.  103,000. 

NOTE. — The  practical  value  is  about  ^  of  the  above. 

CEMENTS    FOR    STEAM    BOILERS,  ,STEAM    PIPES,    ETC. 

Soft  Cement. — Red  and  white  lead  in  oil  4  parts,  sifted  iron  borings  2  to  3  parts. 

RUST     JOINTS. 

For  Quick  Setting. — i  Ib.  of  salammoniac  in  powder,  2  Ibs.  flower  of  sulphur, 
Solbs.  of  iron  borings;  made  to  paste  with  water. 

Slow  Setting. — 2 Ibs.  salammoniac,   lib.  of  sulphur,  20 Ibs.  of  iron  borings. 


BISHOP'S 


FOR  ABOVE  OR  BELOW  WATER  LINE. 

No  Valves  or  Cocks  to  Turn  On  or  Off. 


Patented  and  Manufactured  by 

WILLIAM     BISHOP, 
House,  Yacht  &  Ship  Plumber, 

COPPERSMITH  AND  STEAM  FITTER. 
210  SOUTH   ST.,   N.  Y 

YACHT    PLUMBING    A    SPECIALTY. 


CANOE  AND  YACHT  BOOKS. 

Published  and  For  Sale  by  the  Forest  and  Stream  Publishing  Co. 

Canoe  and  Boat  Building.—  A  complete  manual  for  amateurs.  Containing  plain  and 
comprehensive  directions  for  the  construction  of  canoes,  rowing  and  sailing  boats  and  hunting 
craft.  By  W.  P.  Stephens,  canoeing  editor  of  Forest  and  Stream.  With  numerous  Illustrations 
and  twenty-nine  plates  of  working  drawings.  Cloth,  189  pages,  plates  In  an  envelope.  Price  81.50. 

Canoe  Handling.—  The  Canoe:  History,  Uses,  Limitations  and  Varieties,  Practical  Manage- 
ment and  Care,  and  Relative  Facts.  By  C.  Bowyer  Vaux  ("Dot").  Illustrated.  Cloth,  168  pages. 
Price  $1.00.  A  complete  manual  for  the  management  of  the  canoe. 

Canoe  and  Camp  Cookery.—  A  Practical  Cook  Book  for  Canoeists,  Corinthian  Sailors  and 
Outers.  By  "Seneca."  Cloth,  96  pages.  Price,  $1.00.  Full  and  plain  instructions  about  outfit  and 
cooking  utensils. 

Small  Yachts.—  Small  Yachts:  Their  Design  and  Construction,  Exemplified  by  the  Ruling 
Types  of  Modern  Practice.  With  numerous  plates  and  Illustrations.  By  C.  P.  Kunhardt.  Cloth, 
370  pag 


, 

illustrations  and  70  plates.  Size  of  page  14^x12^.  Price,  $7.00.  This  book  is 
Intended  to  cover  the  field  of  small  yachts,  with  special  regard  to  their  design,  construction, 
equipment  and  keep.  Among  the  plates  will  be  found  many  famous  and  well-known  vessels, 
illustrated  with  great  detail  and  finish. 

Steam  Yachts  and  Launches.—  Their  Machinery  and  Management.  By  C.  P.  Kunhardt. 
With  plates  and  many  illustrations.  Cloth,  250  pages.  Price,  $3.00. 

Yachts,  Boats  and  Canoes.—  With  special  chapters  on  model  yachts  and  slnglehanded 
sailing.  By  C.  Stansfleld-Hicks.  Numerous  illustrations  and  diagrams,  and  working  drawings  of 
model  yachts  and  various  small  craft  suitable  for  amateurs.  Cloth.  Price,  $3.50. 

Knot*.  Ties  and  Splices.—  A  handbook  for  seafarers,  travelers  and  all  who  use  cordage. 
By  J.  Tom  Burgess.  Illustrated.  Cloth,  101  pages.  Price,  50  cents.  Gives  all  the  useful  knots 
and  illustrates  them  Intelligently. 

The  Canoe  A  urora.—  A  Cruise  from  the  Adirondacks  to  the  Gulf.  By  Dr.  Chas.  A.  Neide,  ex- 
Secretary  of  the  American  Canoe  Association.  Cloth,  215  pages,  with  map  of  the  route.  Price,  31. 

Four  Months  in  a  Sneakbox.—  A  boat  voyage  or  2,600  miles  down  the  Ohio  and  Missis- 
sippi Rivers,  and  along  the  Gulf  of  Mexico.  By  Nathaniel  H.  Bishop.  With  diagram  of  sneakbox 
and  other  illustrations.  Cloth,  322  pages.  Price,  $1.50. 

Woods  and  Lakes  of  Maine.—  A  trip  from  Moosehead  Lake  to  New  Brunswick,  with  large 
map  of  Moosehead  Lake  and  Northern  Maine,  with  soundings  in  Moosehead  Lake.  By  Lucius  L. 
Hubbard.  Handsomely  illustrated  and  bound,  223  pages.  Price,  $3. 

Canvas  Canoes;  How  to  Build  Them.—  A  complete  manual  of  instruction  for  building  cheap, 
safe  canvas  canoes.  By  Parker  B.  Field.  With  a  plan  and  all  dimensions,  and  other  Illustrations. 
Paper,  48  pages.  Price,  50  cents. 

Model  Yachts  and  Boats.—  Their  Designing,  Making  and  Sailing.  By  J.  du  V.  Grosvenor. 
Illustrated  with  121  designs  and  working  drawings.  Leatherette,  183  pages.  Price,  $2.00. 

Woodcraft.—  By  "Nessmuk."  Cloth,  160  pages.  Illustrated.  Price,  $1.00.  A  book  written  for 
the  instruction  and  guidance  of  those  who  go  for  pleasure  to  the  woods. 

OUTDOOR  BOOKS.—  The  Forest  and  Stream  Publishing  Co.'s  descriptive  Catalogue  of 
books  on  Shooting,  Angling,  Camping  and  Outdoor  Life,  will  be  sent  free  to  any  address. 

Forest  and  Stream  Publishing  Co.*  4O  Park  Row,  New  York. 

HOUSTON  &  WOODBRIDGE, 

ENGINEERS 


AND 

Iron   Ship   Builders, 

STEAM  AND  SAILING  YACHTS. 

P.  O.  Linwood,  Delaware  Co.,  Pa. 


J.   BEAVOR-WEBB, 


45    BROADWAY,  NEW    YORK. 


Flanged  Plates, 
Boiler  Plates 


AND 


Blooms. 


AGENT    FOR 

FOX'S  PATENT 
CORRUGATED 

Boiler  Furnaces1 

Manufactured  by 

The  Leeds  Forge  Co.ggg  Best  Yorkshire  Steel 

OF  ENGLAND,       ^^Si^^M^^^^^^^iiiti^  (SIEMENS'). 

FITTED   IN    THE   AMERICAN   STEAM   YACHTS 

"Corsair"  "Stranger"  "Peerless"  "Susquehanna5 

AND     OTHERS. 


Muir  &  Caldwell's  Steam  Steering  Gear. 

VICKER'S     STEEL    SHAFTING. 

Steam  Yachts  and  Pleasure  Boats. 

PETROLEUM    AS     FUEL. 

Seven  sizes  of  Steam  Yachts,  19 
to  40  ft.  long.  Designed  for  Yacht 
Tenders,  Pleasure,  Cruising  and 
Hunting  purposes.  Fine  models 
and  workmanship.  Light,  speedy 
and  seaworthy.  No  noise,  smoke 
or  dirt.  No  danger.  No  smell.  Perfect  combustion.  Petroleum  as  fuel.  Eco- 
nomical and  clean.  Easy  to  operate.  Marine  and  Stationary  Engines  and  Boilers. 
Yacht  fittings.  SEND  STAMPS  FOR  CATALOGUE. 

Celebrated  Racine  Boats  and  Ca- 
noes. Veneer  Canoes  with  life  com- 
partments. Hunting  aud  Fishing 
Boats.  Cedar  Lapstreak  Boats.  Boat 
Fittings. 

SEND    STAMPS   FOR    CATALOGUE. 

THOMAS    KANE    &    CO., 


137  &  139  Wabash  Avenue, 

CHICAGO,  ILL. 


Racine,  Wisconsin, 

U.  S.  A. 


Four  Unrivaled   Products  for 
Yachtsmen. 

DIXON'S 

"Potlead"  for  Yacht  Bottoms. 

Specially  prepared   for  the  purpose,    and   unequalled   for 
Purity  and   Uniformity  of  Grain. 

"Pot  leading"  is  of  value  in  proportion  to  the  quality  of  the  article  used. 
DIXON'S  BLACK  LEAD  is  a  pure  graphite  ground  to  a  fine  and  even  grain, 
so  that  there  is  no  waste;  and  the  vessel's  bottom  treated  with  it  will  be  of  surpris- 
ing smoothness.  It  will  also  be  found  a  protection  to  the  bottom. 


DIXON'S  GXATE  PAINT. 

It  is  a  mixture  of  perfected  graphite  and  pure  linseed  oil,  so  thoroughly  mixed 
that,  when  applied  with  the  brush,  the  iron  receives  a  coating  of  the  thin  flakes  of 
graphite,  and  this  coating  once  secured,  the  metal  will  stand  any  heat  it  will  ever 
receive.  For  smoke-stacks,  boiler  fronts,  wire  cables  and  all  metal  work  it  is  with- 
out an  equal.  

Dixon's  Graphite  Grease. 

For  gears,  for  loose-fitting  journals  and  bearings,  or  indeed  for  any  friction  sur- 
faces whatever  where  the  conditions  are  such  that  a  grease  can  be  introduced,  we 
guarantee  perfect  usefulness.  A  little  of  this  grease  does  a  great  deal  of  work. 


Dixon's  Dry  Graphite. 

Dixon's  water-dressed  Dry  Foliated  American  Graphite  is  a  little  thin  flake  of 
graphite  of  extraordinary  properties.  It  has  unrivaled  smoothness  and  endurance. 
Its  superiority  as  a  lubricant  has  been  attested  by  all  recent  writers  on  friction. 

Its  enduring  qualities  are  several  times  greater  than  those  of  any  oil.  Unlike 
either  oil  or  grease,  it  is  not  affected  by  heat,  cold,  steam,  acids,  etc.,  and  acts 
equally  well  under  the  most  varying  conditions  of  temperature  and  moisture. 

JOS.  DIXON  CRUCIBLE  CO., 

JERSEY    CITY,  N.  J. 
New  York  Office,  68  Reade  Street. 


COLT  Disc  MARINE  ENGINE. 

NOISELESS     and    ECONOMICAL. 


BEST  PROPELLER  ENGINE  IN  THE  WORLD  FOR 

YACHTS,    TUGS    AND    LAUNCHES. 

It  occupies  small  space,  runs  at  high  speed,  has  no  dead  centers,  is  self-inclosed, 
has  few  wearing  parts,  uniform  wear.  Constructed  in  the  best  manner  and  of  the 
best  materials.  Easily  operated  by  any  one. 

Dimensions,  Etc.,  of  Marine  Engines  (Standard). 


er  of  Pistons 

Total 
Weight. 

i 
;r  of  Cylinder 
ng  over  all. 

PIPE 
CONNECTIONS. 

PPOPORTIONS  OF  BOAT  AND  PRO- 
PELLER FOR  WHICH  ENGINE 
is  SUITED. 

Prices  include 
Reversing 
Gear,  Thrust 
Block, 
Coupling  and 

«• 

BOAT.             PROPELLER. 

B 

4-1          4-» 

3 

o 

Automatic 

9 

1        J 

V 

x 

a 

<£ 

Ej 

Lubricator. 

5 

in 

9 

3 

1 

1 

rt 

Q 

In. 

Lbs. 

In. 

In. 

In. 

Ft. 

Ft. 

In. 

In. 

2 

1  80 

II 

X 

I 

25 

6 

25 

18X18 

)  ci 

$235.00 

3 

500 

I5# 

I 

IK 

35 

8 

30 

24X24  \  H|  . 

327.00 

4 

II5O 

20^ 

I* 

2 

45 

9 

35 

32X34 

•o 

475-oo 

5 

2000 

25 

*x. 

2 

50 

10 

40 

36X40 

rt 

735-00 

6 

2800 

29^ 

I# 

^ 

60 

12 

50 

42X48 

1 

1,055.00 

7 

3800 

32^ 

* 

•|f 

75 

14 

60 

48X54J     ^ 

1,370.00 

Colt's  Patent  Fire  Arms  M'f'g  Co., 

HARTFORD,    CONN. 


io.  OAR  MILLS.  HEPTUNE  ANCHOR  WORKS, 


DE  GRAUW,  AYMAR  &  Co.s 

MANUFACTURERS  AND  IMPORTERS  OF 

CORDAGE,  OAKUM, 
WIRE  ROPE, 

Chains,  Anchors,  Oars,  Blocks, 

Buntings,    Flags, 

Cotton  and  Flax  Ducks, 

Russia  Bolt  Rope. 

Marine  Hardware  and  Ship  Chandlers'  Goods  Generally. 


Nos.  34  AND  35  SOUTH  STREET, 

NEW    YORK. 


Small  Steam  Yachts 


AND 


STEAM     LAUNCHES. 

OF    EITHER 

WOOD    OR    STEEL. 


MACHINERY. 

High     Pressure     Non-Condensing,     Compound     Non- 
Condensing,   Compound  Jet  and  Surface 
Condensing,   Triple    Expansion 
Surface    Condensing. 

Our  boats  are  not  experimental,  but  are  powerful,  fast,  and  economical  of  fuel. 
Burn  either  coal  or  wood.  Can  refer  to  them  in  successful  operation  in  all  parts 
of  the  United  States.  Illustrated  catalogue,  including  engines,  boilers,  propeller 
wheels,  also  six  photographs  of  finished  launches,  sent  on  receipt  of  I2c.  in  stamps. 

CHAS.    P.   WILLARD    <&,    CO., 

236  Randolph  Street,  Chicago,  111. 


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